Suppose, we have an array of objects where the user names are mapped to some unique ids like this −
const arr = [ {"4": "Rahul"}, {"7": "Vikram"}, {"6": "Rahul"}, {"3": "Aakash"}, {"5": "Vikram"} ];
As apparent in the array, same names can have more than one ids but same ids can be used to map two different names.
We are required to write a JavaScript function that takes in one such array as the first argument and a name string as the second argument. The function should return an array of all ids that were used to map the name provided as second argument.
Following is the code −
const arr = [ {"4": "Rahul"}, {"7": "Vikram"}, {"6": "Rahul"}, {"3": "Aakash"}, {"5": "Vikram"} ]; const name = 'Vikram'; const findUserId = (arr, name) => { const res = []; for(let i = 0; i < arr.length; i++){ const key = Object.keys(arr[i])[0]; if(arr[i][key] !== name){ continue; }; res.push(key); }; return res; }; console.log(findUserId(arr, name));
This will produce the following output in console −
['7', '5']