How to get a key in a JavaScript object by its value?

Question

I have a quite simple JavaScript object, which I use as an associative array. Is there a simple function allowing me to get the key for a value, or do I have to iterate the object and find it out manually?

Answer 1

function getKeyByValue(object, value) {   return Object.keys(object).find(key => object[key] === value); } 

ES6, no prototype mutations or external libraries.

Example,

function getKeyByValue(object, value) {    return Object.keys(object).find(key => object[key] === value);  }      const map = {"first" : "1", "second" : "2"};  console.log(getKeyByValue(map,"2"));