Map Objects JavaScript new Map()

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Thu Jun 30 2022 00:09:45 GMT+0000 (Coordinated Universal Time)

// Create New map
const MapObject = new Map();

// Insert New Elements 
MapObject.set("One" , 1 ) ;

// Map has size property count elements
console.log("Map Size  : " , MapObject.size)
// expect output to be  Map Size  : 1

// Map Key Could be any Thing 

MapObject.set(2 , "Two");
console.log("Map Size  : " , MapObject.size)
// expect output to be  Map Size  : 2


MapObject.set( {body : 3} , "Three");
console.log("Map Size  : " , MapObject.size)
// expect output to be  Map Size  : 3

console.log ("Map Object : " , MapObject)
// expect output to be Map Object :  Map(3) {'One' => 1, 2 => 'Two', {…} => 'Three'}

// Map Object  unlike object it's iterable .entries() , .Keys() , .values()
let values = []
for (let item of MapObject.entries()) {
   values.push( item)
}
console.log ("array values :" , values)

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A Map holds key-value pairs where the keys can be any datatype. A Map remembers the original insertion order of the keys. A Map has a property that represents the size of the map. Method Description new Map() Creates a new Map object set() Sets the value for a key in a Map get() Gets the value for a key in a Map clear() Removes all the elements from a Map delete() Removes a Map element specified by a key has() Returns true if a key exists in a Map forEach() Invokes a callback for each key/value pair in a Map entries() Returns an iterator object with the [key, value] pairs in a Map keys() Returns an iterator object with the keys in a Map values() Returns an iterator object of the values in a Map Property Description size Returns the number of Map elements

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map

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Map Objects JavaScript new Map()

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