Jquery how to find an Object by attribute in an Array

Question

Given I have an array of \"purpose\" objects:

//array of purpose objects:
var purposeObjects = [
    {purpose: \"daily\"},
    {purpose: \"weekly\"},
    {pu         


        

Answer 1

Use the Underscore.js findWhere function (http://underscorejs.org/#findWhere):

var purposeObjects = [
    {purpose: "daily"},
    {purpose: "weekly"},
    {purpose: "monthly"}
];

var daily = _.findWhere(purposeObjects, {purpose: 'daily'});

daily would equal:

{"purpose":"daily"}

Here's a fiddle: http://jsfiddle.net/spencerw/oqbgc21x/

To return more than one (if you had more in your array) you could use _.where(...)

Answer 2

No need for jQuery.

JavaScript arrays have a find method, so you can achieve that in one line:

array.find((o) => { return o[propertyName] === propertyValue }

Example

const purposeObjects = [
    {purpose: "daily"},
    {purpose: "weekly"},
    {purpose: "monthly"}
];

purposeObjects.find((o) => { return o["purpose"] === "weekly" }

// output -> {purpose: "weekly"}

If you need IE compatibility, import this polyfill in your code.

Answer 3

you should pass reference on item in grep function:

function findPurpose(purposeName){
    return $.grep(purposeObjects, function(item){
      return item.purpose == purposeName;
    });
};

Example

Answer 4

If your array is actually a set of JQuery objects, what about simply using the .filter() method ?

purposeObjects.filter('[purpose="daily"]')

Answer 5

copied from polyfill Array.prototype.find code of Array.find, and added the array as first parameter.

you can pass the search term as predicate function

// Example
var listOfObjects = [{key: "1", value: "one"}, {key: "2", value: "two"}]
var result = findInArray(listOfObjects, function(element) {
  return element.key == "1";
});
console.log(result);

// the function you want
function findInArray(listOfObjects, predicate) {
      if (listOfObjects == null) {
        throw new TypeError('listOfObjects is null or not defined');
      }

      var o = Object(listOfObjects);

      var len = o.length >>> 0;

      if (typeof predicate !== 'function') {
        throw new TypeError('predicate must be a function');
      }

      var thisArg = arguments[1];

      var k = 0;

      while (k < len) {
        var kValue = o[k];
        if (predicate.call(thisArg, kValue, k, o)) {
          return kValue;
        }
        k++;
      }

      return undefined;
}

Answer 6

Javascript has a function just for that: Array.prototype.find. As example

function isBigEnough(element) {
  return element >= 15;
}

[12, 5, 8, 130, 44].find(isBigEnough); // 130

It not difficult to extends the callback to a function. However this is not compatible with IE (and partially with Edge). For a full list look at the Browser Compatibility