{"id":15697,"date":"2024-01-15T17:01:10","date_gmt":"2024-01-15T13:31:10","guid":{"rendered":"https:\/\/rasanegar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/"},"modified":"2024-01-15T17:01:10","modified_gmt":"2024-01-15T13:31:10","slug":"%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85","status":"publish","type":"post","link":"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/","title":{"rendered":"\u0627\u067e\u0631\u0627\u062a\u0648\u0631 Null Coalescing \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0627 ECMAScript 2020 \u0647\u0646\u06af\u0627\u0645 \u06a9\u0627\u0631 \u062f\u0631 \u0686\u0631\u062e\u0647 \u0639\u0645\u0631 \u062f\u0631\u062e\u0648\u0627\u0633\u062a-\u067e\u0627\u0633\u062e\u060c \u0645\u06cc\u200c\u062e\u0648\u0627\u0647\u06cc\u062f \u0645\u0637\u0645\u0626\u0646 \u0634\u0648\u06cc\u062f \u06a9\u0647 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0628\u0627 \u0628\u062f\u0646 \u0645\u0648\u0631\u062f \u0646\u0638\u0631 &#8211; \u06cc\u0627 \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0622\u0645\u0648\u0632\u0646\u062f\u0647 \u062f\u0631\u06cc\u0627\u0641\u062a \u0645\u06cc\u200c\u0634\u0648\u062f \u062a\u0627 \u06a9\u0644\u0627\u06cc\u0646\u062a \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u06a9\u0646\u0646\u062f\u0647 \u062f\u0627\u062f\u0647 \u062f\u0631 \u062d\u0644\u0642\u0647 \u0628\u0627\u0642\u06cc \u0628\u0645\u0627\u0646\u062f.  \u062f\u0631 \u0635\u0648\u0631\u062a \u0648\u062c\u0648\u062f \u0645\u0642\u0627\u062f\u06cc\u0631 \u062a\u0647\u06cc\u060c \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u064b \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0646\u062a\u06cc\u062c\u0647 \u0645\u062a\u0641\u0627\u0648\u062a\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f."},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-custom ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\"><p class=\"ez-toc-title\" style=\"cursor:inherit\">\u0633\u0631\u0641\u0635\u0644\u0647\u0627\u06cc \u0645\u0637\u0644\u0628<\/p>\n<\/div><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/#%d9%85%d8%b9%d8%b1%d9%81%db%8c\" >\u0645\u0639\u0631\u0641\u06cc<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/#%d8%a7%d8%aa%d8%b5%d8%a7%d9%84_%da%a9%d9%88%d8%aa%d8%a7%d9%87_%da%86%db%8c%d8%b3%d8%aa%d8%9f\" >\u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0686\u06cc\u0633\u062a\u061f<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/#%d8%a7%d8%b1%d8%b2%d8%b4_%d9%87%d8%a7%db%8c_%d8%af%d8%b1%d8%b3%d8%aa_%d9%88_%d9%86%d8%a7%d8%af%d8%b1%d8%b3%d8%aa\" >\u0627\u0631\u0632\u0634 \u0647\u0627\u06cc \u062f\u0631\u0633\u062a \u0648 \u0646\u0627\u062f\u0631\u0633\u062a<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/#%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1_%d8%a7%d8%af%d8%ba%d8%a7%d9%85_%d9%86%d8%a7%d9%82%d8%b5\" >\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0627\u062f\u063a\u0627\u0645 \u0646\u0627\u0642\u0635<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/rasanegaar.com\/blog\/%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1-null-coalescing-%d8%af%d8%b1-%d8%ac%d8%a7%d9%88%d8%a7-%d8%a7%d8%b3%da%a9%d8%b1%db%8c%d9%be%d8%aa-%d8%a8%d8%a7-ecmascript-2020-%d9%87%d9%86%da%af%d8%a7%d9%85\/#%d9%86%d8%aa%db%8c%d8%ac%d9%87\" >\u0646\u062a\u06cc\u062c\u0647<\/a><\/li><\/ul><\/nav><\/div>\n<span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">\u0632\u0645\u0627\u0646 \u0644\u0627\u0632\u0645 \u0628\u0631\u0627\u06cc \u0645\u0637\u0627\u0644\u0639\u0647: <\/span> <span class=\"rt-time\"> 5<\/span> <span class=\"rt-label rt-postfix\">\u062f\u0642\u06cc\u0642\u0647<\/span><\/span><p> <br \/>\n<\/p>\n<div class=\"content\"><noscript><\/p>\n<style>.lazyload-placeholder { display: none;  }<\/style>\n<p><\/noscript><\/p>\n<h2 id=\"introduction\"><span class=\"ez-toc-section\" id=\"%d9%85%d8%b9%d8%b1%d9%81%db%8c\"><\/span>\u0645\u0639\u0631\u0641\u06cc<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0647\u0646\u06af\u0627\u0645 \u06a9\u0627\u0631 \u062f\u0631 a <em>\u0686\u0631\u062e\u0647 \u0639\u0645\u0631 \u062f\u0631\u062e\u0648\u0627\u0633\u062a-\u067e\u0627\u0633\u062e<\/em>\u060c \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0645\u0637\u0645\u0626\u0646 \u0634\u0648\u06cc\u062f \u06a9\u0647 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0628\u0627 \u0628\u062f\u0646 \u0645\u0648\u0631\u062f \u0646\u0638\u0631 &#8211; \u06cc\u0627 \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0622\u0645\u0648\u0632\u0646\u062f\u0647 \u0645\u06cc \u0631\u0633\u062f \u062a\u0627 \u0645\u0634\u062a\u0631\u06cc \u06a9\u0647 \u062f\u0627\u062f\u0647 \u0631\u0627 \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u06a9\u0631\u062f\u0647 \u062f\u0631 \u062d\u0644\u0642\u0647 \u0628\u0645\u0627\u0646\u062f.  \u062f\u0631 \u0635\u0648\u0631\u062a <strong>\u0645\u0642\u0627\u062f\u06cc\u0631 \u062a\u0647\u06cc<\/strong>\u060c \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u064b \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0646\u062a\u06cc\u062c\u0647 \u0645\u062a\u0641\u0627\u0648\u062a\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f.<\/p>\n<p>\u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u0637\u0645\u0626\u0646 \u0634\u062f \u06a9\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646 \u0628\u0627 \u0622\u0646 \u0627\u06cc\u0646 \u06a9\u0627\u0631 \u0631\u0627 \u0627\u0646\u062c\u0627\u0645 \u062f\u0627\u062f <strong>\u0639\u0645\u0644\u06af\u0631 \u0628\u0627\u0637\u0644<\/strong> \u0647\u0645\u0686\u0646\u06cc\u0646 \u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0634\u0646\u0627\u062e\u062a\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 Null Coalescing<\/strong>\u060c \u06a9\u0647 \u0628\u0627 \u0627\u0636\u0627\u0641\u0647 \u0634\u062f\u0646 \u0628\u0647 \u0632\u0628\u0627\u0646 <em>ECMAScript 2020<\/em>.  \u0628\u0627 \u0622\u0646\u060c \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u0645\u0642\u062f\u0627\u0631\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f <em>\u06cc\u0627<\/em> \u0628\u0633\u062a\u0647 \u0628\u0647 \u0645\u0642\u062f\u0627\u0631 \u062f\u06cc\u06af\u0631\u06cc\u060c \u0622\u0646 \u0631\u0627 \u0628\u0647 \u0645\u0642\u062f\u0627\u0631 \u062f\u06cc\u06af\u0631\u06cc \u0627\u062e\u062a\u0635\u0627\u0635 \u062f\u0647\u06cc\u062f \u0631\u0648\u06cc \u06cc\u06a9 \u0639\u0628\u0627\u0631\u062a \u0628\u0648\u0644\u06cc<\/p>\n<blockquote>\n<p>\u0627\u06af\u0631 \u0645\u0642\u062f\u0627\u0631 \u062f\u06cc\u06af\u0631\u06cc \u0648\u062c\u0648\u062f \u0646\u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u062f\u060c \u0645\u06cc \u062a\u0648\u0627\u0646 \u0627\u0632 \u0627\u06cc\u0646 \u0628\u0631\u0627\u06cc \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f\u0646 \u0645\u0642\u0627\u062f\u06cc\u0631 \u067e\u06cc\u0634 \u0641\u0631\u0636 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0631\u062f. <em>\u06cc\u0627<\/em> \u0628\u0631\u0627\u06cc \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f\u0646 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0645\u062e\u062a\u0644\u0641 \u0628\u0631 \u0627\u0633\u0627\u0633 \u0631\u0648\u06cc \u0647\u0631 \u0639\u0628\u0627\u0631\u062a \u0628\u0648\u0644\u06cc \u062f\u06cc\u06af\u0631<\/p>\n<\/blockquote>\n<p>\u0631\u0627 <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 Null Coalescing<\/strong> \u0645\u062a\u0639\u0644\u0642 \u0628\u0647 \u06af\u0631\u0648\u0647 \u0627\u0633\u062a <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631\u0647\u0627\u06cc \u0645\u0646\u0637\u0642\u06cc \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647<\/strong>\u060c \u06a9\u0647 \u062f\u0631 \u06cc\u06a9 \u0644\u062d\u0638\u0647 \u0646\u06af\u0627\u0647\u06cc \u0628\u0647 \u0622\u0646 \u062e\u0648\u0627\u0647\u06cc\u0645 \u062f\u0627\u0634\u062a.<\/p>\n<p>\u062a\u0627 \u062d\u062f\u0648\u062f\u06cc \u0634\u0628\u06cc\u0647 \u0628\u0647 <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0645\u0634\u0631\u0648\u0637<\/strong>\u060c \u06a9\u0647 \u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u0628\u0647 \u0622\u0646 \u0645\u0639\u0631\u0648\u0641 \u0627\u0633\u062a <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0633\u0647 \u062a\u0627\u06cc\u06cc<\/strong>:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-comment\">\/\/ Null Coalescing Operator<\/span>\n<span class=\"hljs-comment\">\/\/ If the left-hand side is null, the right-hand side is returned<\/span>\nresult = nullValue ?? defaultValue\n\n<span class=\"hljs-comment\">\/\/ Conditional Operator<\/span>\n<span class=\"hljs-comment\">\/\/ If the condition is true, the left side is assigned, otherwise, the right side is assigned<\/span>\ncondition ? value : value2\n<\/code><\/pre>\n<blockquote>\n<p>\u062f\u0631 \u0627\u06cc\u0646 \u0631\u0627\u0647\u0646\u0645\u0627\u060c \u0646\u06af\u0627\u0647\u06cc \u0628\u0647 \u0627\u06cc\u0646 \u062e\u0648\u0627\u0647\u06cc\u0645 \u062f\u0627\u0634\u062a <strong>nullish\/Null Coalescing Operator\u060c \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0648 \u0645\u0642\u0627\u062f\u06cc\u0631 \u062f\u0631\u0633\u062a \u0648 \u0646\u0627\u062f\u0631\u0633\u062a<\/strong> &#8211; \u0627\u0632 \u0637\u0631\u06cc\u0642 \u0645\u062b\u0627\u0644 \u0647\u0627\u06cc \u0639\u0645\u0644\u06cc<\/p>\n<\/blockquote>\n<h2 id=\"whatisshortcircuiting\"><span class=\"ez-toc-section\" id=\"%d8%a7%d8%aa%d8%b5%d8%a7%d9%84_%da%a9%d9%88%d8%aa%d8%a7%d9%87_%da%86%db%8c%d8%b3%d8%aa%d8%9f\"><\/span>\u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0686\u06cc\u0633\u062a\u061f<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0627\u067e\u0631\u0627\u062a\u0648\u0631\u0647\u0627 \u0631\u0627 \u0627\u0632 \u0686\u067e \u0628\u0647 \u0631\u0627\u0633\u062a \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0645\u06cc \u06a9\u0646\u062f.  \u0628\u0627 \u0627\u067e\u0631\u0627\u062a\u0648\u0631\u0647\u0627\u06cc \u0627\u0646\u062d\u0635\u0627\u0631\u06cc \u06a9\u0647 \u062f\u0631 \u0622\u0646 \u0646\u06cc\u0627\u0632 \u062f\u0627\u0631\u06cc\u0645 <strong>\u0647\u0631 \u062f\u0648<\/strong> \u0645\u0642\u0627\u062f\u06cc\u0631 \u0628\u0631\u0627\u06cc \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0635\u062d\u06cc\u062d\u060c \u06af\u0627\u0647\u06cc \u0627\u0648\u0642\u0627\u062a \u06a9\u0627\u0641\u06cc \u0627\u0633\u062a \u0641\u0642\u0637 \u0627\u0648\u0644\u06cc\u0646 \u0639\u0628\u0627\u0631\u062a \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0631\u0627 \u0628\u0631\u0631\u0633\u06cc \u06a9\u0646\u06cc\u062f.<\/p>\n<p>\u0627\u06af\u0631 \u0633\u0645\u062a \u0686\u067e \u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0628\u0627\u0634\u062f <code>false<\/code>\u060c \u0635\u0631\u0641 \u0646\u0638\u0631 \u0627\u0632 \u0633\u0645\u062a \u0631\u0627\u0633\u062a\u060c \u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0646\u062a\u06cc\u062c\u0647 \u0645\u06cc \u062f\u0647\u062f <code>false<\/code>\u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u0627\u0631\u0632\u0634\u06cc\u0627\u0628\u06cc \u0637\u0631\u0641 \u0645\u0642\u0627\u0628\u0644 \u0641\u0627\u06cc\u062f\u0647 \u0627\u06cc \u0646\u062f\u0627\u0631\u062f \u0648 \u0628\u0631\u0627\u06cc \u062d\u0641\u0638 \u0642\u062f\u0631\u062a \u0645\u062d\u0627\u0633\u0628\u0627\u062a\u06cc \u0627\u0632 \u0622\u0646 \u0635\u0631\u0641 \u0646\u0638\u0631 \u0645\u06cc \u0634\u0648\u062f.<\/p>\n<blockquote>\n<p>\u0627\u06cc\u0646 process \u0646\u0627\u0645\u06cc\u062f\u0647 \u0645\u06cc\u0634\u0648\u062f <strong>\u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647<\/strong>.<\/p>\n<\/blockquote>\n<p>\u0642\u0628\u0644 \u0627\u0632 ES2020\u060c \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u062a\u0646\u0647\u0627 \u062f\u0648 \u0639\u0645\u0644\u06af\u0631 \u0645\u0646\u0637\u0642\u06cc \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u062f\u0627\u0634\u062a:<\/p>\n<ul>\n<li>\u0639\u0645\u0644\u06af\u0631 \u0645\u0646\u0637\u0642\u06cc <em>\u0648<\/em> &#8211; <code>&amp;&amp;<\/code><\/li>\n<li>\u0639\u0645\u0644\u06af\u0631 \u0645\u0646\u0637\u0642\u06cc <em>\u06cc\u0627<\/em> &#8211; <code>||<\/code><\/li>\n<\/ul>\n<p>\u0628\u0627 \u0622\u067e\u062f\u06cc\u062a \u062c\u062f\u06cc\u062f\u060c \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u06cc\u06a9\u06cc \u062f\u06cc\u06af\u0631 \u0631\u0627 \u0645\u0639\u0631\u0641\u06cc \u06a9\u0631\u062f:<\/p>\n<ul>\n<li><em>\u0627\u062f\u063a\u0627\u0645 \u067e\u0648\u0686<\/em> \u0627\u067e\u0631\u0627\u062a\u0648\u0631 &#8211; <code>??<\/code><\/li>\n<\/ul>\n<p>\u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0628\u0647 \u062e\u0648\u062f\u06cc \u062e\u0648\u062f \u06a9\u062f \u0631\u0627 \u06a9\u0627\u0631\u0622\u0645\u062f\u062a\u0631 \u0645\u06cc\u200c\u06a9\u0646\u062f\u060c \u0632\u06cc\u0631\u0627 \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc\u200c\u0647\u0627\u06cc \u06a9\u0645\u062a\u0631\u06cc \u0646\u06cc\u0627\u0632 \u0627\u0633\u062a\u060c \u0647\u0631\u0686\u0646\u062f\u060c \u0627\u0632 \u0637\u0631\u06cc\u0642 \u0639\u0645\u0644\u06af\u0631 Null Coalescing\u060c \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u06cc\u0645 \u0645\u0646\u0637\u0642 \u06a9\u062f \u0631\u0627 \u0646\u06cc\u0632 \u0628\u0631 \u0627\u0633\u0627\u0633 \u062a\u063a\u06cc\u06cc\u0631 \u062f\u0647\u06cc\u0645. \u0631\u0648\u06cc \u06cc\u06a9 \u0639\u0645\u0644\u06cc\u0627\u062a \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647<\/p>\n<p>\u0628\u0631\u0627\u06cc \u0645\u062b\u0627\u0644:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-keyword\">let<\/span> x = <span class=\"hljs-number\">10<\/span>;\n<span class=\"hljs-keyword\">let<\/span> y = <span class=\"hljs-number\">20<\/span>;\n\n<span class=\"hljs-keyword\">let<\/span> result;\n\n<span class=\"hljs-keyword\">if<\/span> (x+y &gt; <span class=\"hljs-number\">20<\/span>){\n    result = <span class=\"hljs-string\">\"x+y is greater than 20\"<\/span>;\n}\n\n<span class=\"hljs-built_in\">console<\/span>.log(result);\n<\/code><\/pre>\n<p>\u0627\u06cc\u0646 \u06a9\u062f \u0646\u062a\u06cc\u062c\u0647 \u062e\u0648\u0627\u0647\u062f \u062f\u0627\u062f:<\/p>\n<pre><code class=\"hljs\">x+y is greater than 20\n<\/code><\/pre>\n<p>\u0627\u06af\u0631\u0686\u0647\u060c \u0645\u0627 \u0647\u0645\u0686\u0646\u06cc\u0646 \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u06cc\u0645 \u0622\u0646 \u0631\u0627 \u06a9\u0646\u0627\u0631 \u0628\u06af\u0630\u0627\u0631\u06cc\u0645 <code>if<\/code> \u0639\u0628\u0627\u0631\u062a \u0631\u0627 \u0628\u0647 \u0637\u0648\u0631 \u06a9\u0627\u0645\u0644 \u0628\u06cc\u0627\u0646 \u06a9\u0646\u06cc\u062f \u0648 \u0628\u0647 \u062c\u0627\u06cc \u0622\u0646 \u0627\u0632 \u0639\u0645\u0644\u06af\u0631 \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0648 \u0628\u0631\u0627\u06cc \u06a9\u0648\u062a\u0627\u0647 \u06a9\u0631\u062f\u0646 \u0639\u0628\u0627\u0631\u0627\u062a \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u062f:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-keyword\">let<\/span> x = <span class=\"hljs-number\">10<\/span>;\n<span class=\"hljs-keyword\">let<\/span> y = <span class=\"hljs-number\">20<\/span>;\n\n(x+y) &gt; <span class=\"hljs-number\">20<\/span> &amp;&amp; <span class=\"hljs-built_in\">console<\/span>.log(<span class=\"hljs-string\">\"x+y is greater than 20\"<\/span>);\n<\/code><\/pre>\n<p><code>(x+y) &gt; 20<\/code>  \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0645\u06cc \u06a9\u0646\u062f <code>true<\/code> \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u0628\u0644\u0648\u06a9 \u0628\u0639\u062f\u06cc \u0648\u0627\u0631\u062f \u0645\u06cc \u0634\u0648\u062f \u0648 \u067e\u06cc\u0627\u0645 \u0686\u0627\u067e \u0645\u06cc \u0634\u0648\u062f.<\/p>\n<blockquote>\n<p>\u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0627\u06cc\u0646\u062c\u0627 \u06a9\u062c\u0627\u0633\u062a\u061f<\/p>\n<\/blockquote>\n<p>\u0627\u06af\u0631 <code>(x+y) &gt; 20<\/code> \u0628\u0648\u062f <em>\u062f\u0631\u0648\u063a\u06cc\u0646<\/em> (\u062f\u0631 \u06cc\u06a9 \u062b\u0627\u0646\u06cc\u0647 \u062f\u0631 \u0645\u0648\u0631\u062f \u0627\u06cc\u0646 \u0635\u062d\u0628\u062a \u062e\u0648\u0627\u0647\u06cc\u0645 \u06a9\u0631\u062f)\u060c \u0645\u0641\u0633\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u062d\u062a\u06cc \u0628\u0647 \u0642\u0633\u0645\u062a \u062f\u0648\u0645 \u0639\u0628\u0627\u0631\u062a \u0646\u06af\u0627\u0647 \u0646\u0645\u06cc \u06a9\u0646\u062f\u060c \u0648 \u0628\u0644\u0648\u06a9 \u0647\u0631\u06af\u0632 \u0627\u062c\u0631\u0627 \u0646\u0645\u06cc \u0634\u0648\u062f.<\/p>\n<p>\u0628\u0647 \u0637\u0648\u0631 \u0645\u0634\u0627\u0628\u0647\u060c \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u0645 \u0627\u0632 \u0639\u0645\u0644\u06af\u0631 \u0645\u0646\u0637\u0642\u06cc OR \u0628\u0647 \u0631\u0648\u0634\u06cc \u0645\u0634\u0627\u0628\u0647 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u0645:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-keyword\">let<\/span> x = <span class=\"hljs-number\">10<\/span>;\n<span class=\"hljs-keyword\">let<\/span> y = <span class=\"hljs-number\">20<\/span>;\n\n(x-y) &gt; <span class=\"hljs-number\">0<\/span> || <span class=\"hljs-built_in\">console<\/span>.log(<span class=\"hljs-string\">\"x+y is lesser than 0\"<\/span>);\n<\/code><\/pre>\n<p>\u0628\u0647 \u0637\u0648\u0631 \u0637\u0628\u06cc\u0639\u06cc\u060c \u0627\u06cc\u0646 \u0646\u062a\u06cc\u062c\u0647 \u0645\u06cc \u0634\u0648\u062f:<\/p>\n<pre><code class=\"hljs\">x+y is lesser than 0\n<\/code><\/pre>\n<p>\u0627\u06cc\u0646 \u0645\u062b\u0627\u0644 \u0647\u0627 \u0628\u0633\u06cc\u0627\u0631 \u0633\u0627\u062f\u0647 \u0647\u0633\u062a\u0646\u062f\u060c \u0627\u0645\u0627 \u0639\u0645\u0644\u06af\u0631\u0647\u0627\u06cc \u0645\u0646\u0637\u0642\u06cc \u0645\u06cc \u062a\u0648\u0627\u0646\u0646\u062f \u0628\u0633\u06cc\u0627\u0631\u06cc \u0627\u0632 \u0645\u0634\u06a9\u0644\u0627\u062a \u0639\u0645\u0644\u06cc \u0631\u0627 \u062d\u0644 \u06a9\u0646\u0646\u062f \u0648 \u06a9\u062f \u0634\u0645\u0627 \u0631\u0627 \u0628\u0633\u06cc\u0627\u0631 \u062a\u0645\u06cc\u0632\u062a\u0631 \u06a9\u0646\u0646\u062f.  \u0628\u0627 \u0627\u06cc\u0646 \u062d\u0627\u0644\u060c \u0627\u06af\u0631 \u0628\u0647 \u062f\u0631\u0633\u062a\u06cc \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0646\u0634\u0648\u062f\u060c \u0645\u0645\u06a9\u0646 \u0627\u0633\u062a \u0628\u0631\u0627\u06cc \u062e\u0648\u062f \u0633\u0631\u062f\u0631\u062f \u0627\u06cc\u062c\u0627\u062f \u06a9\u0646\u06cc\u062f.<\/p>\n<h2 id=\"truthyandfalsyvalues\"><span class=\"ez-toc-section\" id=\"%d8%a7%d8%b1%d8%b2%d8%b4_%d9%87%d8%a7%db%8c_%d8%af%d8%b1%d8%b3%d8%aa_%d9%88_%d9%86%d8%a7%d8%af%d8%b1%d8%b3%d8%aa\"><\/span>\u0627\u0631\u0632\u0634 \u0647\u0627\u06cc \u062f\u0631\u0633\u062a \u0648 \u0646\u0627\u062f\u0631\u0633\u062a<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0648\u0642\u062a\u06cc \u0628\u0627 \u0639\u0645\u0644\u06af\u0631\u0647\u0627\u06cc \u0645\u0646\u0637\u0642\u06cc \u06a9\u0627\u0631 \u0645\u06cc \u06a9\u0646\u06cc\u062f\u060c \u0628\u0627 \u0627\u06cc\u0646 \u0634\u0631\u0627\u06cc\u0637 \u0622\u0634\u0646\u0627 \u062e\u0648\u0627\u0647\u06cc\u062f \u0634\u062f <em>\u0627\u0631\u0632\u0634 \u0648\u0627\u0642\u0639\u06cc<\/em> \u0648 <em>\u0627\u0631\u0632\u0634 \u06a9\u0627\u0630\u0628<\/em>.<\/p>\n<p>\u0622 <strong>\u0627\u0631\u0632\u0634 \u0648\u0627\u0642\u0639\u06cc<\/strong> \u0647\u0631 \u0627\u0631\u0632\u0634\u06cc \u0627\u0633\u062a <strong>\u0627\u06cc\u0646 \u0646\u06cc\u0633\u062a:<\/strong><\/p>\n<ul>\n<li><code>null<\/code><\/li>\n<li><code>undefined<\/code><\/li>\n<li><code>0<\/code><\/li>\n<li><code>''<\/code>  &#8211; \u0631\u0634\u062a\u0647 \u062e\u0627\u0644\u06cc<\/li>\n<li><code>false<\/code><\/li>\n<li><code>NaN<\/code>  &#8211; \u06cc\u06a9 \u0639\u062f\u062f \u0646\u06cc\u0633\u062a<\/li>\n<\/ul>\n<p>\u0647\u0645\u0647 \u0627\u06cc\u0646 \u0645\u0642\u0627\u062f\u06cc\u0631 \u062f\u0631 \u0646\u0638\u0631 \u06af\u0631\u0641\u062a\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a <strong>\u062f\u0631\u0648\u063a\u06cc\u0646<\/strong>.<\/p>\n<p>\u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\u060c \u0647\u0645\u0647 <em>\u0627\u0631\u0632\u0634 \u0647\u0627\u06cc \u063a\u0644\u0637<\/em> \u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0645\u06cc \u0634\u0648\u0646\u062f <code>false<\/code> \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u062f\u0631 \u062d\u0644\u0642\u0647 \u0647\u0627 \u06cc\u0627 <code>if<\/code> \u0628\u06cc\u0627\u0646\u06cc\u0647 \u0647\u0627 \u0648 \u0647\u0645\u0647 <em>\u0627\u0631\u0632\u0634 \u0647\u0627\u06cc \u0648\u0627\u0642\u0639\u06cc<\/em> \u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0627\u0631\u0632\u06cc\u0627\u0628\u06cc \u0645\u06cc \u0634\u0648\u0646\u062f <code>true<\/code>.<\/p>\n<p>\u0627\u06a9\u0646\u0648\u0646 \u06a9\u0647 \u067e\u06cc\u0634 \u0646\u06cc\u0627\u0632\u0647\u0627 \u0631\u0627 \u067e\u0648\u0634\u0634 \u062f\u0627\u062f\u0647 \u0627\u06cc\u0645\u060c \u062f\u0631 \u0646\u0647\u0627\u06cc\u062a \u0627\u062c\u0627\u0632\u0647 \u062f\u0647\u06cc\u062f \u0646\u06af\u0627\u0647\u06cc \u0628\u0647 \u0622\u0646 \u0628\u06cc\u0627\u0646\u062f\u0627\u0632\u06cc\u0645 <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0628\u0627\u0637\u0644<\/strong>.<\/p>\n<h2 id=\"nullishcoalescingoperator\"><span class=\"ez-toc-section\" id=\"%d8%a7%d9%be%d8%b1%d8%a7%d8%aa%d9%88%d8%b1_%d8%a7%d8%af%d8%ba%d8%a7%d9%85_%d9%86%d8%a7%d9%82%d8%b5\"><\/span>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0627\u062f\u063a\u0627\u0645 \u0646\u0627\u0642\u0635<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u067e\u0648\u0686<\/strong> \u0628\u0631\u0631\u0633\u06cc \u0645\u06cc \u06a9\u0646\u062f \u06a9\u0647 \u0622\u06cc\u0627 \u0645\u0642\u062f\u0627\u0631 \u0627\u0633\u062a <strong>\u0628\u0627\u0637\u0644 \u06a9\u0631\u062f\u0646<\/strong>\u060c \u0646\u0647 <strong>\u062f\u0631\u0648\u063a\u06cc\u0646<\/strong>.  \u0622 <strong>\u0627\u0631\u0632\u0634 \u0628\u0627\u0637\u0644<\/strong> \u0627\u0633\u062a <code>undefined<\/code> \u06cc\u0627 <code>null<\/code>.<\/p>\n<blockquote>\n<p>\u0627\u06cc\u0646 \u0628\u0647 \u0645\u0627 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc \u062f\u0647\u062f \u062a\u0627 \u0632\u0645\u0627\u0646\u06cc \u06a9\u0647 \u0627\u0632 \u0646\u062a\u0627\u06cc\u062c \u0645\u0637\u0645\u0626\u0646 \u0646\u06cc\u0633\u062a\u06cc\u0645\u060c \u0645\u0642\u0627\u062f\u06cc\u0631 \u063a\u06cc\u0631 \u062a\u0647\u06cc \u067e\u06cc\u0634 \u0641\u0631\u0636 \u0631\u0627 \u0628\u0647 \u0645\u062a\u063a\u06cc\u0631\u0647\u0627 \u0627\u062e\u062a\u0635\u0627\u0635 \u062f\u0647\u06cc\u0645.<\/p>\n<\/blockquote>\n<p>\u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0645\u062b\u0627\u0644\u060c \u0628\u06cc\u0627\u06cc\u06cc\u062f \u0633\u0631\u0648\u06cc\u0633 \u06a9\u0627\u0631\u0628\u0631\u06cc \u0631\u0627 \u0645\u0633\u062e\u0631\u0647 \u06a9\u0646\u06cc\u0645 \u06a9\u0647 \u06a9\u0627\u0631\u0628\u0631 \u0631\u0627 \u0627\u0632 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 \u0628\u0627\u0632\u06cc\u0627\u0628\u06cc \u0645\u06cc \u06a9\u0646\u062f \u0648 \u0646\u0627\u0645 \u0627\u0648 \u0631\u0627 \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f.  \u0627\u062d\u062a\u0645\u0627\u0644 \u0627\u06cc\u0646\u06a9\u0647 \u06a9\u0627\u0631\u0628\u0631 \u0648\u062c\u0648\u062f \u0646\u062f\u0627\u0634\u062a\u0647 \u0628\u0627\u0634\u062f 10 \u062f\u0631\u0635\u062f \u0627\u0633\u062a \u06a9\u0647 \u062a\u0648\u0633\u0637 a \u062a\u0646\u0638\u06cc\u0645 \u0645\u06cc \u0634\u0648\u062f <code>Math.random()<\/code> \u0632\u0646\u06af \u0632\u062f\u0646.  \u062f\u0631 10 \u062a\u0645\u0627\u0633 \u0628\u0627 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647\u060c \u0645\u0627 \u0628\u0647 \u0627\u062d\u062a\u0645\u0627\u0644 \u0632\u06cc\u0627\u062f \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9 \u06a9\u0627\u0631\u0628\u0631 \u06af\u0645 \u0634\u062f\u0647 \u0631\u0627 \u062e\u0648\u0627\u0647\u06cc\u0645 \u062f\u06cc\u062f &#8211; \u06a9\u0647 \u0628\u0627 \u0639\u0644\u0627\u0645\u062a \u0646\u0634\u0627\u0646 \u062f\u0627\u062f\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a. <code>null<\/code> \u0646\u062a\u06cc\u062c\u0647:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-class\"><span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">DbConnection<\/span> <\/span>{\n  <span class=\"hljs-function\"><span class=\"hljs-title\">find<\/span>(<span class=\"hljs-params\">id<\/span>)<\/span> {\n    <span class=\"hljs-keyword\">if<\/span> (<span class=\"hljs-built_in\">Math<\/span>.random() &gt; <span class=\"hljs-number\">0.9<\/span>) {\n      <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-literal\">null<\/span>;\n    } <span class=\"hljs-keyword\">else<\/span> {\n      <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-string\">`John Doe <span class=\"hljs-subst\">${id}<\/span>`<\/span>;\n    }\n  }\n}\n\n<span class=\"hljs-keyword\">const<\/span> db = <span class=\"hljs-keyword\">new<\/span> DbConnection();\n\n<span class=\"hljs-keyword\">for<\/span> (<span class=\"hljs-keyword\">let<\/span> i = <span class=\"hljs-number\">0<\/span>; i &lt; <span class=\"hljs-number\">10<\/span>; i++) {\n  <span class=\"hljs-keyword\">let<\/span> user = db.find(i);\n\n  <span class=\"hljs-keyword\">if<\/span> (user != <span class=\"hljs-literal\">null<\/span>){\n    <span class=\"hljs-built_in\">console<\/span>.log(user);\n  } <span class=\"hljs-keyword\">else<\/span> {\n    <span class=\"hljs-built_in\">console<\/span>.log(<span class=\"hljs-string\">'User not found'<\/span>);\n  }\n}\n<\/code><\/pre>\n<p>\u06a9\u062f \u062e\u0631\u0648\u062c\u06cc \u06cc\u0627 \u0646\u0627\u0645 \u06cc\u0627 \u067e\u06cc\u0627\u0645\u06cc \u0631\u0627 \u0646\u0634\u0627\u0646 \u0645\u06cc \u062f\u0647\u062f \u06a9\u0647 \u0646\u0634\u0627\u0646 \u062f\u0647\u0646\u062f\u0647 \u0639\u062f\u0645 \u0648\u062c\u0648\u062f \u06a9\u0627\u0631\u0628\u0631 \u062f\u0631 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 \u0627\u0633\u062a\u060c \u0627\u06af\u0631\u0686\u0647 \u0627\u06cc\u0646 \u0627\u0645\u0631 \u0645\u0633\u062a\u0644\u0632\u0645 \u0627\u0646\u062c\u0627\u0645 \u0628\u0631\u0631\u0633\u06cc \u0647\u0627\u06cc \u062a\u0647\u06cc \u062f\u0631 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 \u0627\u0633\u062a. <code>if<\/code> \u0628\u06cc\u0627\u0646\u06cc\u0647.<\/p>\n<p>\u0627\u06cc\u0646 \u0646\u062a\u06cc\u062c\u0647 \u062f\u0631:<\/p>\n<pre><code class=\"hljs\">John Doe 0\nJohn Doe 1\nUser not found\nJohn Doe 3\nJohn Doe 4\nJohn Doe 5\nUser not found\nUser not found\nJohn Doe 8\nJohn Doe 9\n<\/code><\/pre>\n<p>\u0628\u0647 \u0637\u0648\u0631 \u0627\u062a\u0641\u0627\u0642\u06cc\u060c \u0628\u0647 \u0646\u0638\u0631 \u0645\u06cc \u0631\u0633\u062f \u0627\u06cc\u0646 \u06cc\u06a9 \u0627\u062c\u0631\u0627 \u0639\u062c\u06cc\u0628 \u0648 \u063a\u0631\u06cc\u0628 \u0627\u0633\u062a &#8211; 3 <code>null<\/code> \u0646\u062a\u0627\u06cc\u062c!  \u0627\u06cc\u0646 \u06a9\u062f \u0628\u0647 \u062e\u0648\u0628\u06cc \u06a9\u0627\u0631 \u0645\u06cc \u06a9\u0646\u062f \u0648 \u06a9\u0627\u0631 \u0645\u06cc \u06a9\u0646\u062f <code>null<\/code> \u0645\u0648\u0627\u0631\u062f \u0627\u06af\u0631 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647 a \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f <code>null<\/code> \u0627\u0631\u0632\u0634.<\/p>\n<p>\u0627\u0632 \u0637\u0631\u0641 \u062f\u06cc\u06af\u0631\u060c \u0645\u06cc\u200c\u062a\u0648\u0627\u0646\u06cc\u0645 \u0627\u0632 \u0686\u06cc\u0632 \u0628\u0633\u06cc\u0627\u0631 \u0645\u062e\u062a\u0635\u0631\u062a\u0631\u06cc \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0646\u06cc\u0645:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-class\"><span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title\">DbConnection<\/span> <\/span>{\n  <span class=\"hljs-function\"><span class=\"hljs-title\">find<\/span>(<span class=\"hljs-params\">id<\/span>)<\/span> {\n    <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-built_in\">Math<\/span>.random() &gt; <span class=\"hljs-number\">0.9<\/span> ? <span class=\"hljs-literal\">null<\/span> : <span class=\"hljs-string\">`John Doe <span class=\"hljs-subst\">${id}<\/span>`<\/span>\n  }\n}\n\n<span class=\"hljs-keyword\">const<\/span> db = <span class=\"hljs-keyword\">new<\/span> DbConnection();\n\n<span class=\"hljs-keyword\">for<\/span> (<span class=\"hljs-keyword\">let<\/span> i = <span class=\"hljs-number\">0<\/span>; i &lt; <span class=\"hljs-number\">10<\/span>; i++) {\n  <span class=\"hljs-keyword\">let<\/span> user = db.find(i) ?? <span class=\"hljs-string\">\"User not found\"<\/span>\n  <span class=\"hljs-built_in\">console<\/span>.log(user)\n}\n<\/code><\/pre>\n<p>\u0628\u0627 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0627\u0632 a <em>\u0639\u0645\u0644\u06af\u0631 \u0634\u0631\u0637\u06cc<\/em>\u060c \u0645\u0627 \u0647\u0645 \u0628\u0631\u06af\u0634\u062a\u06cc\u0645 <code>null<\/code> \u06cc\u0627 <code>John Doe<\/code> \u0628\u0627 \u0634\u0646\u0627\u0633\u0647 \u0645\u0631\u0628\u0648\u0637\u0647 \u062e\u0648\u062f  \u0627\u06af\u0631 <code>Math.random() &gt; 0.9<\/code>\u060c <code>null<\/code> \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f\u0647 \u0634\u062f\u0647 \u0627\u0633\u062a\u060c \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u0628\u0647 \u0627\u062d\u062a\u0645\u0627\u0644 10\u066a \u0628\u0627\u0632\u06af\u0631\u062f\u0627\u0646\u062f\u0647 \u0645\u06cc \u0634\u0648\u062f \u0631\u0648\u06cc \u0647\u0631 \u062a\u0645\u0627\u0633 \u0628\u0627 \u067e\u0627\u06cc\u06af\u0627\u0647 \u062f\u0627\u062f\u0647<\/p>\n<p>\u0633\u067e\u0633 \u0628\u0627 \u0641\u0631\u0636 \u0627\u0645\u06a9\u0627\u0646 <code>null<\/code> \u0645\u0642\u0627\u062f\u06cc\u0631 &#8211; \u0645\u0627 \u0627\u0632 \u0622\u0646 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u06a9\u0631\u062f\u0647 \u0627\u06cc\u0645 <strong>\u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0628\u0627\u0637\u0644<\/strong> \u0628\u0631\u0627\u06cc \u0627\u062e\u062a\u0635\u0627\u0635 \u06cc\u06a9 \u0645\u0642\u062f\u0627\u0631 \u062c\u062f\u06cc\u062f \u0628\u0647 <code>user<\/code> \u0646\u062a\u06cc\u062c\u0647 \u0627\u06af\u0631 \u0645\u0639\u0644\u0648\u0645 \u0634\u0648\u062f <code>null<\/code>.  \u0627\u06af\u0631 <code>db.find()<\/code> \u0628\u0631\u0645\u06cc \u06af\u0631\u062f\u0627\u0646\u062f <code>null<\/code>\u060c \u0645\u0642\u062f\u0627\u0631 \u0633\u0645\u062a \u0631\u0627\u0633\u062a \u0648\u0627\u0631\u062f \u0645\u06cc \u0634\u0648\u062f \u0648 \u0628\u0647 \u062c\u0627\u06cc \u0622\u0646 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f\u0647 \u0645\u06cc \u0634\u0648\u062f.<\/p>\n<p>\u0627\u06cc\u0646 \u06a9\u062f \u0628\u0633\u06cc\u0627\u0631 \u062a\u0645\u06cc\u0632\u062a\u0631 \u0648 \u06a9\u0648\u062a\u0627\u0647\u062a\u0631 \u0627\u0632 \u06a9\u062f \u0627\u0633\u062a <code>if-else<\/code> \u0627\u0638\u0647\u0627\u0631\u0627\u062a\u060c \u0648 <code>if-else<\/code> \u0639\u0628\u0627\u0631\u0627\u062a \u062a\u0645\u0627\u06cc\u0644 \u0628\u06cc\u0634\u062a\u0631\u06cc \u0628\u0647 \u0622\u0628\u0634\u0627\u0631 \u062f\u0627\u0631\u0646\u062f \u0648 \u062d\u062a\u06cc \u067e\u06cc\u0686\u06cc\u062f\u0647 \u062a\u0631 \u0645\u06cc \u0634\u0648\u0646\u062f.  \u0627\u06af\u0631\u0686\u0647\u060c \u062e\u0648\u0627\u0646\u062f\u0646 \u0686\u0646\u062f\u06cc\u0646 \u0627\u067e\u0631\u0627\u062a\u0648\u0631 \u0627\u062a\u0635\u0627\u0644 \u06a9\u0648\u062a\u0627\u0647 \u0632\u0646\u062c\u06cc\u0631 \u0634\u062f\u0647 \u0646\u06cc\u0632 \u062f\u0634\u0648\u0627\u0631 \u0627\u0633\u062a\u060c \u0628\u0646\u0627\u0628\u0631\u0627\u06cc\u0646 \u062c\u0627\u06cc\u06af\u0632\u06cc\u0646 \u06a9\u0631\u062f\u0646 \u0622\u0646 \u0648\u0627\u0642\u0639\u0627\u064b \u062a\u0648\u0635\u06cc\u0647 \u0646\u0645\u06cc \u0634\u0648\u062f. <em>\u0647\u0645\u0647<\/em> <code>if-else<\/code>  \u0628\u0644\u0648\u06a9 \u0647\u0627:<\/p>\n<pre><code class=\"hljs\"><span class=\"hljs-keyword\">let<\/span> s1 = (<span class=\"hljs-built_in\">Math<\/span>.random() &gt; <span class=\"hljs-number\">0.5<\/span> ? <span class=\"hljs-number\">1<\/span> : <span class=\"hljs-literal\">null<\/span>) ?? (<span class=\"hljs-built_in\">Math<\/span>.random() &gt; <span class=\"hljs-number\">0.5<\/span> ? <span class=\"hljs-number\">4<\/span> : (<span class=\"hljs-built_in\">Math<\/span>.random() &gt; <span class=\"hljs-number\">0.5<\/span> ? <span class=\"hljs-literal\">null<\/span> : <span class=\"hljs-number\">1<\/span>))\n\n<span class=\"hljs-built_in\">console<\/span>.log(s1)\n<\/code><\/pre>\n<p>\u0645\u06cc\u062f\u0648\u0646\u06cc \u0627\u06cc\u0646 \u0686\u06cc \u0645\u06cc\u0634\u0647 print?  \u0628\u0627 \u062f\u0631 \u0646\u0638\u0631 \u06af\u0631\u0641\u062a\u0646 \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u062a \u062a\u0635\u0627\u062f\u0641\u06cc\u060c \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u064b \u06a9\u0645\u06cc \u0637\u0648\u0644 \u0645\u06cc \u06a9\u0634\u062f \u062a\u0627 \u0627\u06cc\u0646 \u0631\u0627 \u0628\u0647 \u0635\u0648\u0631\u062a \u062f\u0633\u062a\u06cc \u062a\u062c\u0632\u06cc\u0647 \u06a9\u0646\u06cc\u062f \u0648 \u0628\u0628\u06cc\u0646\u06cc\u062f \u06a9\u062f\u0627\u0645 \u0645\u0642\u0627\u062f\u06cc\u0631 \u0631\u0627 \u0645\u06cc \u062a\u0648\u0627\u0646\u06cc\u062f \u067e\u06cc\u0634 \u0628\u06cc\u0646\u06cc \u06a9\u0646\u06cc\u062f.  \u0627\u06cc\u0646 \u06a9\u062f \u062a\u0645\u0627\u06cc\u0644 \u0628\u0647 \u0646\u062a\u06cc\u062c\u0647 \u062f\u0627\u0631\u062f <code>1<\/code> \u0628\u0627 <code>null<\/code> \u0648 <code>4<\/code> \u062f\u0631 \u0628\u0631\u062e\u06cc \u0645\u0648\u0627\u0631\u062f\u060c \u0628\u0647 \u0639\u0646\u0648\u0627\u0646 \u0645\u0642\u062f\u0627\u0631 \u067e\u06cc\u0634 \u0641\u0631\u0636 \u0628\u0627\u0632\u06af\u0634\u062a\u06cc \u0628\u0631\u0627\u06cc \u0639\u0645\u0644\u06af\u0631 \u062a\u0647\u06cc \u062f\u0631 \u0627\u06cc\u0646 \u0645\u0648\u0631\u062f \u0627\u0633\u062a <em>\u062a\u0647\u06cc \u062f\u06cc\u06af\u0631<\/em>.  \u0628\u0647 \u0637\u0648\u0631 \u0645\u0639\u0645\u0648\u0644\u060c \u062f\u0631 \u0645\u0648\u0627\u0631\u062f\u06cc \u0645\u0627\u0646\u0646\u062f \u0627\u06cc\u0646\u060c \u0627\u0632 \u0628\u06cc\u0634 \u0627\u0632 \u06cc\u06a9 \u06cc\u0627 \u062f\u0648 \u0639\u0645\u0644\u06af\u0631 \u0627\u0633\u062a\u0641\u0627\u062f\u0647 \u0646\u062e\u0648\u0627\u0647\u06cc\u062f \u06a9\u0631\u062f.<\/p>\n<h2 id=\"conclusion\"><span class=\"ez-toc-section\" id=\"%d9%86%d8%aa%db%8c%d8%ac%d9%87\"><\/span>\u0646\u062a\u06cc\u062c\u0647<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\u0628\u0631\u0627\u06cc \u062c\u0645\u0639 \u0628\u0646\u062f\u06cc \u0627\u06cc\u0646\u060c \u062a\u0646\u0647\u0627 \u0647\u062f\u0641 \u0627\u0632 <em>\u0639\u0645\u0644\u06af\u0631 \u0628\u0627\u0637\u0644<\/em> \u0627\u06cc\u0646 \u0627\u0633\u062a \u06a9\u0647 \u0628\u0647 \u0634\u0645\u0627 \u0627\u062c\u0627\u0632\u0647 \u0645\u06cc \u062f\u0647\u062f \u0647\u0645\u06cc\u0634\u0647 \u0646\u0648\u0639\u06cc \u0645\u0642\u062f\u0627\u0631 \u067e\u06cc\u0634 \u0641\u0631\u0636 \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f\u060c \u0628\u0647 \u062c\u0627\u06cc \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u062f\u0646 \u0686\u06cc\u0632\u06cc \u06a9\u0647 \u0648\u062c\u0648\u062f \u0646\u062f\u0627\u0631\u062f &#8211; \u06a9\u0647 \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a\u060c \u0647\u0645\u0627\u0646 \u0686\u06cc\u0632\u06cc \u0627\u0633\u062a \u06a9\u0647 <code>null<\/code> \u0648 <code>undefined<\/code> \u0645\u0646\u0638\u0648\u0631 \u062f\u0627\u0634\u062a\u0646.<\/p>\n<\/div>\n<p><br \/>\n<br \/>\u0645\u0646\u062a\u0634\u0631 \u0634\u062f\u0647 \u062f\u0631 1403-01-15 17:01:06<br \/>\n<\/p>\n\n\n<div class=\"kk-star-ratings kksr-auto kksr-align-center kksr-valign-bottom\"\n    data-payload='{&quot;align&quot;:&quot;center&quot;,&quot;id&quot;:&quot;15697&quot;,&quot;slug&quot;:&quot;default&quot;,&quot;valign&quot;:&quot;bottom&quot;,&quot;ignore&quot;:&quot;&quot;,&quot;reference&quot;:&quot;auto&quot;,&quot;class&quot;:&quot;&quot;,&quot;count&quot;:&quot;0&quot;,&quot;legendonly&quot;:&quot;&quot;,&quot;readonly&quot;:&quot;&quot;,&quot;score&quot;:&quot;0&quot;,&quot;starsonly&quot;:&quot;&quot;,&quot;best&quot;:&quot;5&quot;,&quot;gap&quot;:&quot;5&quot;,&quot;greet&quot;:&quot;\u0627\u0645\u062a\u06cc\u0627\u0632 \u0634\u0645\u0627 \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0637\u0644\u0628&quot;,&quot;legend&quot;:&quot;0\\\/5 (0 \u0631\u0627\u06cc)&quot;,&quot;size&quot;:&quot;30&quot;,&quot;title&quot;:&quot;\u0627\u067e\u0631\u0627\u062a\u0648\u0631 Null Coalescing \u062f\u0631 \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0628\u0627 ECMAScript 2020 \u0647\u0646\u06af\u0627\u0645 \u06a9\u0627\u0631 \u062f\u0631 \u0686\u0631\u062e\u0647 \u0639\u0645\u0631 \u062f\u0631\u062e\u0648\u0627\u0633\u062a-\u067e\u0627\u0633\u062e\u060c \u0645\u06cc\u200c\u062e\u0648\u0627\u0647\u06cc\u062f \u0645\u0637\u0645\u0626\u0646 \u0634\u0648\u06cc\u062f \u06a9\u0647 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0628\u0627 \u0628\u062f\u0646 \u0645\u0648\u0631\u062f \u0646\u0638\u0631 - \u06cc\u0627 \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0622\u0645\u0648\u0632\u0646\u062f\u0647 \u062f\u0631\u06cc\u0627\u0641\u062a \u0645\u06cc\u200c\u0634\u0648\u062f \u062a\u0627 \u06a9\u0644\u0627\u06cc\u0646\u062a \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u06a9\u0646\u0646\u062f\u0647 \u062f\u0627\u062f\u0647 \u062f\u0631 \u062d\u0644\u0642\u0647 \u0628\u0627\u0642\u06cc \u0628\u0645\u0627\u0646\u062f.  \u062f\u0631 \u0635\u0648\u0631\u062a \u0648\u062c\u0648\u062f \u0645\u0642\u0627\u062f\u06cc\u0631 \u062a\u0647\u06cc\u060c \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u064b \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0646\u062a\u06cc\u062c\u0647 \u0645\u062a\u0641\u0627\u0648\u062a\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f.&quot;,&quot;width&quot;:&quot;0&quot;,&quot;_legend&quot;:&quot;{score}\\\/{best} ({count} \u0631\u0627\u06cc)&quot;,&quot;font_factor&quot;:&quot;1.25&quot;}'>\n            \n<div class=\"kksr-stars\">\n    \n<div class=\"kksr-stars-inactive\">\n            <div class=\"kksr-star\" data-star=\"1\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" data-star=\"2\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" data-star=\"3\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" data-star=\"4\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" data-star=\"5\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n    <\/div>\n    \n<div class=\"kksr-stars-active\" style=\"width: 0px;\">\n            <div class=\"kksr-star\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n            <div class=\"kksr-star\" style=\"padding-left: 5px\">\n            \n\n<div class=\"kksr-icon\" style=\"width: 30px; height: 30px;\"><\/div>\n        <\/div>\n    <\/div>\n<\/div>\n                \n\n<div class=\"kksr-legend\" style=\"font-size: 24px;\">\n            <span class=\"kksr-muted\">\u0627\u0645\u062a\u06cc\u0627\u0632 \u0634\u0645\u0627 \u0628\u0647 \u0627\u06cc\u0646 \u0645\u0637\u0644\u0628<\/span>\n    <\/div>\n    <\/div>\n","protected":false},"excerpt":{"rendered":"<p><span class=\"span-reading-time rt-reading-time\" style=\"display: block;\"><span class=\"rt-label rt-prefix\">\u0632\u0645\u0627\u0646 \u0644\u0627\u0632\u0645 \u0628\u0631\u0627\u06cc \u0645\u0637\u0627\u0644\u0639\u0647: <\/span> <span class=\"rt-time\"> 5<\/span> <span class=\"rt-label rt-postfix\">\u062f\u0642\u06cc\u0642\u0647<\/span><\/span>\u0645\u0639\u0631\u0641\u06cc \u0647\u0646\u06af\u0627\u0645 \u06a9\u0627\u0631 \u062f\u0631 a \u0686\u0631\u062e\u0647 \u0639\u0645\u0631 \u062f\u0631\u062e\u0648\u0627\u0633\u062a-\u067e\u0627\u0633\u062e\u060c \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0645\u0637\u0645\u0626\u0646 \u0634\u0648\u06cc\u062f \u06a9\u0647 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0628\u0627 \u0628\u062f\u0646 \u0645\u0648\u0631\u062f \u0646\u0638\u0631 &#8211; \u06cc\u0627 \u062d\u062f\u0627\u0642\u0644 \u06cc\u06a9 \u067e\u0627\u0633\u062e \u0622\u0645\u0648\u0632\u0646\u062f\u0647 \u0645\u06cc \u0631\u0633\u062f \u062a\u0627 \u0645\u0634\u062a\u0631\u06cc \u06a9\u0647 \u062f\u0627\u062f\u0647 \u0631\u0627 \u062f\u0631\u062e\u0648\u0627\u0633\u062a \u06a9\u0631\u062f\u0647 \u062f\u0631 \u062d\u0644\u0642\u0647 \u0628\u0645\u0627\u0646\u062f. \u062f\u0631 \u0635\u0648\u0631\u062a \u0645\u0642\u0627\u062f\u06cc\u0631 \u062a\u0647\u06cc\u060c \u0627\u062d\u062a\u0645\u0627\u0644\u0627\u064b \u0645\u06cc \u062e\u0648\u0627\u0647\u06cc\u062f \u0646\u062a\u06cc\u062c\u0647 \u0645\u062a\u0641\u0627\u0648\u062a\u06cc \u0631\u0627 \u0628\u0631\u06af\u0631\u062f\u0627\u0646\u06cc\u062f. \u062c\u0627\u0648\u0627 \u0627\u0633\u06a9\u0631\u06cc\u067e\u062a \u0645\u0637\u0645\u0626\u0646 \u0634\u062f \u06a9\u0647 \u0645\u06cc \u062a\u0648\u0627\u0646 [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":9043,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1772,620],"tags":[4141,4142,3218,2508,1252,1840,4149,3535,2830,1781,1967,1779,4150,4148,2387,1841,4151,3690,2428,4078,1780,1103,4143,2588,2573,2301,1796,2750,2494,4145,1774,1803,2450,3515,4144,1956,462,2181,1795,4152,4147,2325,1783,1790,4146,3884,3532,2795,2322,2323,1983,2169,1831,1813],"class_list":["post-15697","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-javascript","category-programming","tag-coalescing","tag-ecmascript","tag-null","tag--javascript","tag--nodejs","tag-1840","tag-4149","tag-3535","tag-2830","tag-1781","tag----nodejs","tag-1779","tag-4150","tag-4148","tag-2387","tag-1841","tag-4151","tag-3690","tag-2428","tag-4078","tag-1780","tag-1103","tag-4143","tag-2588","tag-2573","tag-2301","tag-1796","tag-2750","tag-2494","tag-4145","tag-1774","tag-1803","tag-2450","tag-3515","tag-4144","tag-1956","tag-462","tag-2181","tag-1795","tag-4152","tag-4147","tag-2325","tag-1783","tag-1790","tag-4146","tag-3884","tag-3532","tag-2795","tag-2322","tag--node","tag-1983","tag-2169","tag-1831","tag-1813"],"acf":[],"_links":{"self":[{"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/posts\/15697","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/comments?post=15697"}],"version-history":[{"count":0,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/posts\/15697\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/media\/9043"}],"wp:attachment":[{"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/media?parent=15697"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/categories?post=15697"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rasanegaar.com\/blog\/wp-json\/wp\/v2\/tags?post=15697"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}