JavaScript Map.prototype[@@iterator]() Method
Last Updated :
09 Jan, 2023
Map[@@iterator]( ) method is used to make Map iterable. Map[@@iterator]( ) method returns iterator object which iterates over all code points of Map. Map[@@iterator]( ) is built-in property of Map.
We can use this method by creating Map iterator. We can make Map iterator by calling the @@iterator property. In place of @@iterator, we can use Symbol.iterator constant.
Syntax:
const iter = Map[ Symbol.iterator]();
Parameters: This property does not accept any parameters. Return Value: It returns an iterator to iterating code point of iterator objects.
Example:
JavaScript
<script>
const m = new Map();
m.set(0, "a" )
m.set(2, "b" )
m.set(3, "c" )
const iterator = m[Symbol.iterator]();
let itr = iterator.next()
for (let i = 0; i < script m.size; i++) {
console.log(itr.value, itr.done)
itr = iterator.next()
}
</script>
|
Output:
[0 : 'a'] false
[1 : 'b'] false
[2 : 'c'] false
Example: We can use Map.prototype[@@iterator] method with assign Map to the iterator. We can use for loop to iterate over the code point of Map. The for-of loop uses an iterator to iterate over values of Map.
Javascript
<script>
const m = new Map();
m.set(0, "a" )
m.set(2, "b" )
m.set(3, "c" )
const iterator = m[Symbol.iterator]();
let itr = iterator.next()
for (let i = 0; i < m.size; i++) {
console.log(itr.value)
itr = iterator.next()
}
console.log( "iterating with for-of loop : " )
for (let i of m) {
console.log(i)
}
</script>
|
Output:
[0 : 'a']
[1 : 'b']
[2 : 'c']
iterating with for-of loop :
[0 : 'a']
[1 : 'b']
[2 : 'c']
Supported Browsers:
- Chrome 38 and above
- Edge 12 and above
- Firefox 13 and above
- Internet Explorer 11 and above
- Opera 25 and above
- Safari 8 and above
We have a complete list of Javascript Map methods, to check those please go through this JavaScript MapComplete Reference article.
Like Article
Suggest improvement
Share your thoughts in the comments
Please Login to comment...