Immediately invoked function expression

<p>An immediately invoked function expression (or IIFE, pronounced "iffy", <a href="/facts/International_Phonetic_Alphabet/2e7jmUaG">IPA</a> /ˈɪf.i/) is a <a href="/facts/Programming_idiom/jgggjC2n">programming language idiom</a> which produces a <a href="/facts/Scope_(computer_science)/bbj6AFMo">lexical scope</a> using <a href="/facts/Function_scoping/bbj6AFMo">function scoping</a>. It was popular in <a href="/facts/JavaScript/XhhIIEsl">JavaScript</a> as a method of supporting <a href="/facts/Modular_programming/sNoqKvRD">modular programming</a> before the introduction of more standardized solutions such as <a href="/facts/CommonJS/klw2Y62T">CommonJS</a> and <a href="/facts/ECMAScript/M7nDHsB5">ES modules</a>.
</p><p>Immediately invoked function expressions can be used to avoid <a href="/facts/JavaScript_syntax/TXuGf0g7">variable hoisting</a> from within blocks, protecting against polluting the <a href="/facts/Global_variable/XWF9zC08">global environment</a> and simultaneously allowing public access to methods while retaining privacy for variables defined within the function. In other words, it wraps functions and variables, keeping them out of the global scope and giving them a local scope.
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Immediately invoked function expression open-in-new

Immediately invoked function expression