How to fill a Javascript object literal with many static key/value pairs efficiently?

Question

The typical way of creating a Javascript object is the following:

var map = new Object(); map[myKey1] = myObj1; map[myKey2] = myObj2; 

I need to create such a map where both keys and values are Strings. I have a large but static set of pairs to add to the map.

Is there any way to perform something like this in Javascript:

var map =  { { "aaa", "rrr" }, { "bbb", "ppp" } ... }; 

or do I have to perform something like this for each entry:

map["aaa"]="rrr"; map["bbb"]="ppp"; ... 

Basically, remaining Javascript code will loop over this map and extract values according to criterias known 'at runtime'. If there is a better data structure for this looping job, I am interested too. My objective is to minimize code.

Answer 1

In ES2015 a.k.a ES6 version of JavaScript, a new datatype called Map is introduced.

let map = new Map([["key1", "value1"], ["key2", "value2"]]); map.get("key1"); // => value1 

check this reference for more info.

Answer 2

JavaScript's object literal syntax, which is typically used to instantiate objects (seriously, no one uses new Object or new Array), is as follows:

var obj = {     'key': 'value',     'another key': 'another value',      anUnquotedKey: 'more value!' }; 

For arrays it's:

var arr = [     'value',     'another value',     'even more values' ]; 

If you need objects within objects, that's fine too:

var obj = {     'subObject': {         'key': 'value'     },     'another object': {          'some key': 'some value',          'another key': 'another value',          'an array': [ 'this', 'is', 'ok', 'as', 'well' ]     } } 

This convenient method of being able to instantiate static data is what led to the JSON data format.

JSON is a little more picky, keys must be enclosed in double-quotes, as well as string values:

{"foo":"bar", "keyWithIntegerValue":123}