Search from Array of Objects via Array of Strings in JavaScript

Suppose, we have one array of strings and another array of objects like this −

const arr1 = [ '1956888670', '2109171907', '298845084' ]; const arr2 = [    { KEY: '1262875245', VALUE: 'Vijay Kumar Verma' },    { KEY: '1956888670', VALUE: 'Sivakesava Nallam' },    { KEY: '2109171907', VALUE: 'udm analyst' },    { KEY: '298845084', VALUE: 'Mukesh Nagora' },    { KEY: '2007285563', VALUE: 'Yang Liu' },    { KEY: '1976156380', VALUE: 'Imtiaz Zafar' }, ];

We are required to write a JavaScript function that takes in two such arrays. Then our function should return a filtered version of the second array that contains only those objects whose "KEY" property is listed in the first array as a string.

Example

The code for this will be −

const arr1 = [ '1956888670', '2109171907', '298845084' ]; const arr2 = [    { KEY: '1262875245', VALUE: 'Vijay Kumar Verma' },    { KEY: '1956888670', VALUE: 'Sivakesava Nallam' },    { KEY: '2109171907', VALUE: 'udm analyst' },    { KEY: '298845084', VALUE: 'Mukesh Nagora' },    { KEY: '2007285563', VALUE: 'Yang Liu' },    { KEY: '1976156380', VALUE: 'Imtiaz Zafar' }, ]; const filterByKey = (arr1 = [], arr2 = []) => {    let res = [];    res = arr2.filter(el => {       const { KEY } = el;       const index = arr1.indexOf(KEY);       return index !== -1;    });    return res; }; console.log(filterByKey(arr1, arr2));

Output

And the output in the console will be −

[    { KEY: '1956888670', VALUE: 'Sivakesava Nallam' },    { KEY: '2109171907', VALUE: 'udm analyst' },    { KEY: '298845084', VALUE: 'Mukesh Nagora' } ]