What is the Map.entries() method in TypeScript?
Overview
In TypeScript, a Map is a data structure used to hold key-value pairs of any datatype. The entries() method of the Map class returns an iterator with key-value pairs.
Syntax
let mapObject = new Map()mapObject.entries()
Syntax for Map entries() method in TypeScript
Parameters
This method takes no parameters.
Return value
This method returns an iterator for all the key-value pairs inserted in the Map object.
Note: The returned iterator iterates the key-value pairs in the order of their insertion.
Example
// create some Mapslet evenNumbers = new Map<string, number>([["two", 2], ["four", 4], ["eight", 8]])let cart = new Map<string, number>([["rice", 500], ["bag", 10]])let countries = new Map<string, string>([["NG", "Nigeria"], ["BR", "Brazil"], ["IN", "India"]])let isMarried = new Map<string, boolean>([["James", false], ["Jane", true], ["Doe", false]])let emptyMap = new Map<null, null>()// get the iterators for all Mapslet itr1 = evenNumbers.entries()let itr2 = cart.entries()let itr3 = countries.entries()let itr4 = isMarried.entries()let itr5 = emptyMap.entries()// print out the iteratorsconsole.log(itr1)console.log(itr2)console.log(itr3)console.log(itr4)// print out the entries for any of the iteratorsfor (let entry of itr1) {console.log(entry);}
Explanation
- Lines 2–6: We create five
Mapobjects in TypeScript. - Lines 9–13: We use the
entries()method to get the iterators for eachMapobject. - Lines 16–19: We print the iterators to the console.
- Lines 22: We print the key-value pairs in
itr1one by one using thefor ofloop.