js map add item code example

Example 1: append to map javascript

var myMap = {};

myMap[newKey] = newValue;

// ...


// Another method

var myMap = new Map()
myMap.set("key0","value")
// ...
myMap.has("key1"); // evaluates to false, assuming key1 wasn't set

Example 2: map in javascript

let myMap = new Map()

let keyString = 'a string'
let keyObj    = {}
// setting the values
myMap.set(keyString, "value associated with 'a string'")
myMap.set(keyObj, 'value associated with keyObj')
myMap.set(keyFunc, 'value associated with keyFunc')
myMap.size              // 3
// getting the values
myMap.get(keyString)    // "value associated with 'a string'"
myMap.get(keyObj)       // "value associated with keyObj"
myMap.get(keyFunc)      // "value associated with keyFunc"