What is the best way to iterate through my array of objects using a forEach loop and assign a value to the property of any object that has an empty string?

Inquiry for Part 1: I am currently exploring the use of forEach loop to iterate through an array of objects. My goal is to update the property "profile_image_url" of objects that have an empty string as its value, setting it to a default link ("/media/artist/img_0930-1-9654.jpg"). How can I achieve this efficiently without updating other non-empty values? Attached below is a sample JSON data representing 20000 users.

Inquiry for Part 2: When considering performance and simplicity, which approach would be more favorable: using forEach or a regular for loop for iterating through the array?

JSON Data

[{
    "country": "",
    "artist_id": 4,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="713d0b1e32003d142701084919311409101c011d145f121e1c">[email protected]</a>",
    "profile_image_url": ""
}, {
    "country": "",
    "artist_id": 5,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="f9a9cfb1cece9f97b78f9e9d97b99c81989489959cd79a9694">[email protected]</a>",
    "profile_image_url": ""
}, {
    "country": "US",
    "artist_id": 6,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="0e4d646a6a3a69745d6845433a4e6b766f637e626b206d6163">[email protected]</a>",
    "profile_image_url": "/media/artist/zizmor_039_low_res-1239.jpg"
}, {
    "country": "US",
    "artist_id": 7,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e588dda2d682818daab488a7d3a5809d8488958980cb868a88">[email protected]</a>",
    "profile_image_url": "/media/artist/img_0930-1-7654.jpg"
}]
javascriptarraysjsonloopsforeach

Answer №1

Query Part 1: How do I utilize forEach to iterate through an array of objects and assign a default link/value ("/media/artist/img_0930-1-9654.jpg") to the object property profile_image_url that is currently an empty string?

forEach reference

var arr = [{
  "country": "",
  "artist_id": 4,
  "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="93dfe9fcd0e2dff6c5e3eaabfbd3f6ebf2fee3fff6bdf0fcfe">[email protected]</a>",
  "profile_image_url": ""
}, {
  "country": "",
  "artist_id": 5,
  "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="3363057b0404555d7d4554575d73564b525e435f561d505c5e">[email protected]</a>",
  "profile_image_url": ""
}, {
  "country": "US",
  "artist_id": 6,
  "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="baf9d0dede8eddc0e9dcf1f78efadfc2dbd7cad6df94d9d5d7">[email protected]</a>",
  "profile_image_url": "/media/artist/zizmor_039_low_res-1239.jpg"
}, {
  "country": "US",
  "artist_id": 7,
  "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="fb96c3bcc89c9f93b4aa96b9cdbb9e839a968b979ed5989496">[email protected]</a>",
  "profile_image_url": "/media/artist/img_0930-1-7654.jpg"
}];

// e: element, i: index
arr.forEach(function(e, i) {
  if (e.profile_image_url === '') {
    arr[i].profile_image_url = '/media/artist/img_0930-1-9654.jpg';
  }
});

console.log(arr);
document.write('<pre>' + JSON.stringify(arr, 0, 2) + '</pre>');

Inquiry Part 2: When is it more advantageous to use forEach as opposed to a regular for loop for iteration?

The use of forEach provides benefits of obtaining both the index and value from the array without needing to explicitly set indices such as var i = 0;, access values in the array with arr[i], or use arr.length for iteration.

For more insights visit

Answer №2

Section 1:

var usersList = [{
    "country": "",
    "artist_id": 4,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="296553466a58878c7f59501141694c51484459454c074a4644">[email protected]</a>",
    "profile_image_url": ""
}, {
    "country": "",
    "artist_id": 5,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="712147394646171f3f0716151f311409101c011d145f121e1c">[email protected]</a>",
    "profile_image_url": ""
}, {
    "country": "US",
    "artist_id": 6,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6f2c050b0b5b08153c0924225b2f0a170e021f030a410c0002">[email protected]</a>",
    "profile_image_url": "/media/artist/zizmor_039_low_res-1239.jpg"
}, {
    "country": "US",
    "artist_id": 7,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="9ff2a7d8acf8fbf7d0cef2dda9dffae7fef2eff3fab1fcf0f2">[email protected]</a>",
    "profile_image_url": "/media/artist/img_0930-1-7654.jpg"
}];

usersList.forEach(function(user) {
  if (!user.profile_image_url) {
    user.profile_image_url = "/media/artist/img_0930-1-9654.jpg";
  }
});

document.getElementById('usersList').innerHTML = JSON.stringify(usersList, null, 2);
<pre id="usersList"></pre>

Section 2

There may not be a significant difference when comparing the use of an imperative for loop versus forEach.

An alternative approach you can take is to default to a specified image url when encountering an empty string in the profile_image_url field.

As exemplified with Angular, when binding to a view, if the profile_img_url is blank, utilize the default URL.

var angularModule = angular.module('app', []);

angularModule.controller('MyController', function($scope) {
  $scope.usersList = [{
    "country": "",
    "artist_id": 4,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="216d5b4e62506d447751581949614459404c514d440f424e4c">[email protected]</a>",
    "profile_image_url": ""
  }, {
    "country": "",
    "artist_id": 5,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="87d7b1cfb0b0e1e9c9f1e0e3e9c7e2ffe6eaf7ebe2a9e4e8ea">[email protected]</a>",
    "profile_image_url": ""
  }, {
    "country": "US",
    "artist_id": 6,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="15567f717121726f46735e582155706d74786579703b767a78">[email protected]</a>",
    "profile_image_url": "/media/artist/zizmor_039_low_res-1239.jpg"
  }, {
    "country": "US",
    "artist_id": 7,
    "email": "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="afc297e89cc8cbc7e0fec2ed99efcad7cec2dfc3ca81ccc0c2">[email protected]</a>",
    "profile_image_url": "/media/artist/img_0930-1-7654.jpg"
  }];
});
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.0-beta.1/angular.min.js"></script>
<div ng-app="app" ng-controller="MyController">
  <div ng-repeat="user in usersList">
    <div>Email: {{user.email}}</div>
    <div>Profile Image: {{user.profile_image_url || "/media/artist/img_0930-1-9654.jpg"}}</div>
    <hr>
  </div>
</div>

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