How to Find Element in JavaScript?

find element in array javascript

By Inquisitive Impala on Jul 06, 2020

const simpleArray = [3, 5, 7, 15];
const objectArray = [{ name: 'John' }, { name: 'Emma' }]

console.log( simpleArray.find(e => e === 7) )
// expected output 7

console.log( simpleArray.find(e => e === 10) )
// expected output undefined

console.log( objectArray.find(e => e.name === 'John') )
// expected output { name: 'John' }

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javascript find object by property in array

By SmokeFrog on Apr 20, 2020

// To find a specific object in an array of objects
myObj = myArrayOfObjects.find(obj => obj.prop === 'something');

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javascript find

By Real Rattlesnake on Jul 11, 2020

const inventory = [
  {name: 'apples', quantity: 2},
  {name: 'cherries', quantity: 8}
  {name: 'bananas', quantity: 0},
  {name: 'cherries', quantity: 5}
  {name: 'cherries', quantity: 15}
  
];

const result = inventory.find( ({ name }) => name === 'cherries' );

console.log(result) // { name: 'cherries', quantity: 5 }

Source: developer.mozilla.org

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js find element in array by property

By Expensive Eagle on Jul 30, 2020

var result = jsObjects.find(obj => {
  return obj.b === 6
})

Source: stackoverflow.com

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javascript array.find

By Amused Albatross on Jun 01, 2020

const array1 = [5, 12, 8, 130, 44];

const found = array1.find(element => element > 10);

console.log(found);
// expected output: 12

Source: developer.mozilla.org

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javascript array find

By Coding Random Things on Oct 28, 2020

// Use array.find() like this:

var myArrayOfAges = [1,4,6,8,9,13,16,21,53,78];

var result = myArrayOfAges.find(age => age >= 12);

console.log(result); // Output: 13

/* ------ Below is a polyfill from Mozilla: ------ */

// https://tc39.github.io/ecma262/#sec-array.prototype.find
if (!Array.prototype.find) {
  Object.defineProperty(Array.prototype, 'find', {
    value: function(predicate) {
      // 1. Let O be ? ToObject(this value).
      if (this == null) {
        throw TypeError('"this" is null or not defined');
      }

      var o = Object(this);

      // 2. Let len be ? ToLength(? Get(O, "length")).
      var len = o.length >>> 0;

      // 3. If IsCallable(predicate) is false, throw a TypeError exception.
      if (typeof predicate !== 'function') {
        throw TypeError('predicate must be a function');
      }

      // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
      var thisArg = arguments[1];

      // 5. Let k be 0.
      var k = 0;

      // 6. Repeat, while k < len
      while (k < len) {
        // a. Let Pk be ! ToString(k).
        // b. Let kValue be ? Get(O, Pk).
        // c. Let testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
        // d. If testResult is true, return kValue.
        var kValue = o[k];
        if (predicate.call(thisArg, kValue, k, o)) {
          return kValue;
        }
        // e. Increase k by 1.
        k++;
      }

      // 7. Return undefined.
      return undefined;
    },
    configurable: true,
    writable: true
  });
}

Source: developer.mozilla.org

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