Loop through a 'Hashmap' in JavaScript

Question

I\'m using this method to make artificial \'hashmaps\' in javascript. All I am aiming for is key|value pairs, the actual run time is not important. The method below works fi

Answer 1

for (var i = 0, keys = Object.keys(a_hashmap), ii = keys.length; i < ii; i++) {
  console.log('key : ' + keys[i] + ' val : ' + a_hashmap[keys[i]]);
}

Answer 2

You can use JQuery function

$.each( hashMap, function(index,value){
 console.log("Index = " + index + " value = " + value); 
})

Answer 3

Iterating through a map in vanilla Javacsript is simple .

var map = {...};//your map defined here
for(var index in map)
 {
       var mapKey = index;//This is the map's key.
       for(i = 0 ; i < map[mapKey].length ; i++)
        {
              var mapKeyVal = map[mapKey];//This is the value part for the map's key.


          }
  }

Answer 4

This is an old post, but one way I can think of is

const someMap = { a: 1, b: 2, c: 3 };
Object.keys(someMap)
.map(key => 'key is ' + key + ' value is ' + someMap[key]);

Should this way of iterating be used? Are there any issues with this approach?

Answer 5

Do you mean

for (var i in a_hashmap) { // Or `let` if you're a language pedant :-)
   ...
}

i is undefined when the for-loop gets set up.

Answer 6

Hash maps can be tricky, but quite useful. When iterating over one as you would an object, each key is a tuple with [key, value]:

for (let key of map) {
    console.log('Key is: ' + key[0] + '. Value is: ' + key[1]);
}