ng-defer-load

ng-defer-load is an Angular directive to load elements lazily.

It uses Intersection Observer API to check if an element is in viewport and falls back to scroll detection mechanism for unsupported browsers.

Installation

Using npm:

$ npm i @trademe/ng-defer-load

Usage

1. Import DeferLoadModule into the module corresponding to your component

2. Use the directive with the element you wish to lazy load

  <div
    (deferLoad)="showMyElement=true">
    <my-element
       *ngIf=showMyElement>
      ...
    </my-element>
</div>

Note: You might want to have a loading state for your element with approximately same height as the element.

Server Side Rendering

ng-defer-load supports Server Side Rendering from version 1.1.0

It loads the element on the server by default supporting Search Engine Optimization. If you do not want to pre-render the element in server, you can set preRender to false on the element as below:

  <div
    preRender="false"
    (deferLoad)="showMyElement=true">
    <my-element
       *ngIf=showMyElement>
      ...
    </my-element>
</div>

Demo

Demo of ng-defer-load in use is available here.

License

Released under the MIT license.

Release notes

v1.0.1 - Initial version

v1.1.0 - Supports Universal - Server Side Rendering

v2.0.0 - Supports Angular 6