ng2-go-top-button

A simple customizable go-to-top button component for Angular projects

NOTE: For Angular >= 9 refer to the new NPM package https://www.npmjs.com/ng-go-top-button, new versions of Angular will not be supported in this repository any more.

Versions

For Angular >= "5.0.0" use ">=3.0.0", for Angular < "5.0.0" use "^2.0.0" version of this package.

Installation

npm install ng2-go-top-button --save

Configuration

SystemJS

Register @angular/animations and the package itself in systemjs.config.js as following:

System.config({
    paths: {
      // paths serve as alias
      'npm:': 'node_modules/'
    },
    map: {
        ...
      'ng2-go-top-button': 'npm:ng2-go-top-button',
      '@angular/animations': 'npm:@angular/animations/bundles/animations.umd.js',
      '@angular/animations/browser': 'npm:@angular/animations/bundles/animations-browser.umd.js',
      '@angular/platform-browser/animations': 'npm:@angular/platform-browser/bundles/platform-browser-animations.umd.js',
    },
    packages: {
        ...
       'ng2-go-top-button': {
            defaultExtension: 'js',
            main: './index.js'
      }
    }

API

| Property | Type | Description | | ------ | ------ | ------ | | scrollDistance | number | Number of pixels to be scrolled Y for button to be shown. Defaults to 200px. Must be greater than zero. | | html | string | [Deprecated since v4.0.0] Inner html of button element. Could be an icon or text. Empty by default. | | styles | object | User-defined styles config for the button. | | classNames | string | Custom class names in the following format 'class1 class2 class3'. | | animate | boolean | If true, scrolling will be animated. False by default. | | speed | number | Speedof animated scroll. Must be greater than 1. 80 by default. | | acceleration | number | Number of pixels to speed up when scrolling is animated. 0 by default - this way page will be scrolled top with the constant speed. | | tabIndex | number | Custom tabindex button attribute value, by default 0.

Usage

Import statement:

import {GoTopButtonModule} from 'ng2-go-top-button';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations'; // angular 4.x and greater

Add it to imports in your module declaration. When using angular 4.x and greater, also import a BrowserAnimationsModule:

@NgModule({
    ...
    imports: [..., GoTopButtonModule, BrowserAnimationsModule],
    ...

If you need to export it from your module, than also add it to exports:

@NgModule({
    ...
    exports: [..., GoTopButtonModule]
    ...

On your template paste the <go-top-button></go-top-button> html. This will add a simple button with default styles and without animated scroll. By default go-top-button will appear on the right side, 50% top and bottom and without any icons or text. You can then customize its styles and behaviour.

Example of customization:

<go-top-button   [animate]="true"
                 [speed]="50"
                 [acceleration]="2"
                 [scrollDistance]="300"
                 [classNames]="'custom-class'"
                 [styles]="{
                    'border-radius': '20px 20px 20px 20px',
                    'right': '5px',
                    'color': 'green',
                    'border': '5px solid',
                    'line-height': '20px'
                 }">
        <i class=\'fa fa-arrow-up\'></i>
  </go-top-button>

Custom CSS class declaration (if needed):

.custom-class {
    position: fixed;
    background-color: pink;
    border-color: green;
    height: 30px;
    width: 30px;
}

Note 1:

For the version lower than 4.0.0 of this package you should still use the old syntax of injecting the html:

<go-top-button [html]="'<i class=\'fa fa-arrow-up\'></i>'" ... ></go-top-button>

The new syntax (injecting via <ng-content>) was introduced with v4.0.0 to fix the Angular Material compatibility issues.

Note 2:

In the version 4.2.0 classNames attribute has been added. Now you can define your custom CSS classes in your parent component and apply them to your go top button. In order to achieve this you need to change the CSS encapsulation level of your parent component to either None or Native:

    import { Component, ViewEncapsulation } from '@angular/core';
    
    @Component({
        ...,
        encapsulation: ViewEncapsulation.None, // ViewEncapsulation.Native may also work
    })

This will let your parent component affect the CSS of the go-top-button child.

The default styles now will not be merged with the input styles values - they have been moved to the default CSS class .go-top-button. So if you override this class with your custom className value, you have to write all CSS yourself with no default styling.

IE-specific issues:

IE does not support web animations. If you would like to enable them, install and import the corresponding polyfill to your polyfills.js file:

In your project's directory:

npm install --save web-animations-js

In polyfills.js:

import 'web-animations-js';

Example project

You can find example project that uses ng2-go-top-button in example-app/ directory of this repository. Navigate to this directory and run npm run start, the app will be hosted on http://localhost:4200 (is this port is not taken by any other apps on your host).

Issues & Pull Requests

Feel free to create issues and pull requests. Even though there is a 3.x version of this module for Angular 5, I still support the 2.x version for Angular 4 and lower. Fixes for 2.x version go to the v2-fixes branch.