find and object in array javascript code example

Example 1: javascript find item in array of objects

var __POSTS = [ 
	{ id: 1, title: 'Apple', description: 'Description of post 1' }, 
	{ id: 2, title: 'Orange', description: 'Description of post 2' }, 
	{ id: 3, title: 'Guava', description: 'Description of post 3' }, 
	{ id: 4, title: 'Banana', description: 'Description of post 4' }
];

var __FOUND = __POSTS.find(function(post, index) {
	if(post.title == 'Guava')
		return true;
});

// On success __FOUND will contain the complete element (an object)
// On failure it will contain undefined  
console.log(__FOUND); // { id: 3, title: 'Guava', description: 'Description of post 3' }

Example 2: javascript array find

// 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
  });
}