Immediately invoked function expression: Difference between revisions

Revision as of 21:40, 29 November 2024

Revision as of 21:41, 29 November 2024

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{{Short description|Javascript design pattern}}

An '''immediately invoked function expression''' (or '''IIFE''', pronounced "iffy", [[International Phonetic Alphabet|IPA]] /ˈɪf.i/) is a [[Programming idiom|programming language idiom]] which produces a [[scope (computer science)|lexical scope]] using [[function scoping]]. It was popular in [[JavaScript]]<ref name="Alman">{{cite web|url=http://benalman.com/news/2010/11/immediately-invoked-function-expression/|title=Immediately Invoked Function Expressions|last=Alman|first=Ben|date=15 November 2010|website=|url-status=live|archive-url=https://web.archive.org/web/20171201033208/http://benalman.com/news/2010/11/immediately-invoked-function-expression/|archive-date=1 December 2017|accessdate=18 January 2019}}</ref> as a method of supporting [[modular programming]] before the introduction of more standardized solutions such as [[CommonJS]] and [[ECMAScript#6th Edition – ECMAScript 2015|ES modules]].<ref>{{cite web |last1=McGinnis |first1=Tyler |title=JavaScript Modules: From IIFEs to CommonJS to ES6 Modules |url=https://ui.dev/javascript-modules-iifes-commonjs-esmodules/ |website=ui.dev |access-date=18 August 2021 |language=en |date=15 January 2019}}</ref> It is used to wrap functions and variables, keeping them out of the global scope and giving them a local scope.

Immediately invoked function expressions can be used to avoid [[JavaScript syntax#Scoping and hoisting|variable hoisting]] from within blocks, protecting against polluting the [[Global variable|global environment]] 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.

== Usage ==