how to create for loop in map in javascript?

Question

I want to create for loop statement in map in javascript to update every item in it

var map = new Object();
map[key] = value;
map[key1] = value1;

i want to loop like this:

for(var i = 0; i < map.length; i++)
   //do something for map[key]

however, it´s not clear for me from where can I get map.length and how can I obtain key from i.

[`for..in`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Loops_and_iteration#for...in_statement) is what you looking for — hindmost, May 20 '15 at 10:58
possible duplicate of [javascript: loop through object properties](http://stackoverflow.com/questions/18898743/javascript-loop-through-object-properties) — max, May 20 '15 at 10:58
this is my exactly my question, i want to know how to loop inside map like this map — Malo, May 20 '15 at 11:01

Zee · Answer 1 · 2015-05-20T11:04:16.757

0

To iterate an object you can do something like this:

var map = new Object();
map['key']= 'value';
map['key1'] = 'value1';
//Loop the object key-value pairs
for(var key in map){
 console.log(key + "-->"+ map[key])
}

//OR THIS WAY

var map = new Object();
map.key= 'value';
map.key1 = 'value1';
for(var key in map){
 console.log(key + "-->"+ map.key)
}

edited May 20 '15 at 11:04

answered May 20 '15 at 11:01

Zee

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In addition, is not a bad idea to use dot notations: `map.key`. – kosmos May 20 '15 at 11:02

score 0 · Answer 2 · answered May 20 '15 at 11:04

This is the proper declaration for Map and forEach method to iterate over the map

var usersMap = new Map();
usersMap.set(1, "Malo");
usersMap.set(2, "bob");
usersMap.set(3, "jane");

usersMap.forEach(function (username, userId) {
  console.log(userId, username);
  if (userId === 1) {
     console.log("We found Malo.");
  }
});

how to create for loop in map in javascript?

2 Answers2