Movatterモバイル変換

[0]ホーム
URL:

Menu
×
See More 
Sign In
★+1 Get Certified Upgrade For Teachers Spaces Get Certified Upgrade For Teachers Spaces
   ❮     
     ❯   

Basic JavaScript

JS TutorialJS SyntaxJS VariablesJS OperatorsJS If ConditionsJS LoopsJS StringsJS NumbersJS FunctionsJS ObjectsJS DatesJS ArraysJS Typed ArraysJS SetsJS MapsJS MathJS RegExpJS Data TypesJS ErrorsJS EventsJS ProgrammingJS ReferencesJS Versions

JS Advanced

JS FunctionsJS ObjectsJS ClassesJS IterationsJS AsynchronousJS ModulesJS Meta & ProxyJS HTML DOMJS WindowsJS Web APIJS AJAXJS JSONJS jQueryJS GraphicsJS ExamplesJS Reference


JavaScript Map Reference

Complete Map Reference

Revised July 2025

MethodDescription
new Map()Creates a new Map object
clear()Removes all the elements from a Map
delete()Removes a Map element specified by a key
entries()Returns an iterator object with the [key, value] pairs in a Map
forEach()Invokes a callback for each key/value pair in a Map
get()Gets the value for a key in a Map
groupBy()Groups object elements according to returned callback values
has()Returns true if a key exists in a Map
keys()Returns an iterator object with the keys in a Map
set()Sets the value for a key in a Map
sizeReturns the number of Map elements
values()Returns an iterator object of the values in a Map

×

Contact Sales

If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail:
sales@w3schools.com

Report Error

If you want to report an error, or if you want to make a suggestion, send us an e-mail:
help@w3schools.com

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning.
Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness
of all content. While using W3Schools, you agree to have read and accepted ourterms of use,cookies andprivacy policy.

Copyright 1999-2025 by Refsnes Data. All Rights Reserved.W3Schools is Powered by W3.CSS.

[8]ページ先頭
©2009-2025 Movatter.jp