Vue Prism Editor

A simple code editor with syntax highlighting and line numbers. 3kb/z

Examples

• Codepen: https://codepen.io/bonetino/pen/ZENrpjO

Features

• Code Editing
• Modular syntax highlighting with third party library (not limited to prismjs)
• Indent line or selected text by pressing tab key, with customizable indentation
• Automatic indent on new lines
• Wrap selected text in parens, brackets, or quotes
• Undo / Redo whole words instead of letter by letter
• Accessible, use Ctrl+Shift+M (Mac) / Ctrl+M to toggle capturing tab key
• Works on mobile (thanks to textarea)
• Auto resize
• Line numbers
• Match line numbers styles to the theme(optional)

Use Case

Several browser based code editors such as Ace, CodeMirror, Monaco etc. provide the ability to embed a full-featured code editor in your web page. However, if you just need a simple editor with syntax highlighting without any of the extra features, they can be overkill as they don't usually have a small bundle size footprint. This library aims to provide a simple code editor with syntax highlighting support without any of the extra features, perfect for simple embeds and forms where users can submit code.

Install

1npm install @coscom/vue-prism-editor

or

1yarn add @coscom/vue-prism-editor

Usage

You need to use the editor with a third party library which provides syntax highlighting. For example, it'll look like following with prismjs:

Register the component locally and use it (recommended)

1<template>
2  <prism-editor class="my-editor" v-model="code" :highlight="highlighter" line-numbers></prism-editor>
3</template>
4
5<script>
6  // import Prism Editor
7  import { PrismEditor } from '@coscom/vue-prism-editor';
8  import '@coscom/vue-prism-editor/dist/prismeditor.min.css'; // import the styles somewhere
9
10  // import highlighting library (you can use any library you want just return html string)
11  import { highlight, languages } from 'prismjs/components/prism-core';
12  import 'prismjs/components/prism-clike';
13  import 'prismjs/components/prism-javascript';
14  import 'prismjs/themes/prism-tomorrow.css'; // import syntax highlighting styles
15
16  export default {
17    components: {
18      PrismEditor,
19    },
20    data: () => ({
21      code: 'console.log("Hello World")',
22    }),
23    methods: {
24      highlighter(code) {
25        return highlight(code, languages.js); // languages.<insert language> to return html with markup
26      },
27    },
28  };
29</script>
30
31<style>
32  /* required class */
33  .my-editor {
34    /* we dont use `language-` classes anymore so thats why we need to add background and text color manually */
35    background: #2d2d2d;
36    color: #ccc;
37
38    /* you must provide font-family font-size line-height. Example: */
39    font-family: Fira code, Fira Mono, Consolas, Menlo, Courier, monospace;
40    font-size: 14px;
41    line-height: 1.5;
42    padding: 5px;
43  }
44
45  /* optional class for removing the outline */
46  .prism-editor__textarea:focus {
47    outline: none;
48  }
49</style>

Note that depending on your syntax highlighter, you might have to include additional CSS for syntax highlighting to work.

Or register the component globally

1import { PrismEditor } from '@coscom/vue-prism-editor';
2import '@coscom/vue-prism-editor/dist/prismeditor.min.css'; // import the styles
3Vue.component('PrismEditor', PrismEditor);

Browser usage (for codepen etc.):

1<script src="https://unpkg.com/vue@2.6.*"></script>
2
3<!-- Prism Editor -->
4<script src="https://unpkg.com/@coscom/vue-prism-editor"></script>
5<link rel="stylesheet" href="https://unpkg.com/@coscom/vue-prism-editor/dist/prismeditor.min.css" />
6
7<!-- custom highlighter: -->
8<script src="https://unpkg.com/prismjs/prism.js"></script>
9<link rel="stylesheet" href="https://unpkg.com/prismjs/themes/prism-twilight.css" />
10
11<style>
12  .height-200 {
13    height: 200px;
14  }
15
16  .my-editor {
17    /* we dont use `language-` classes anymore so thats why we need to add background and text color manually */
18    background: #2d2d2d;
19    color: #ccc;
20
21    /* you must provide font-family font-size line-height. Example:*/
22    font-family: Fira code, Fira Mono, Consolas, Menlo, Courier, monospace;
23    font-size: 14px;
24    line-height: 1.5;
25    padding: 5px;
26  }
27
28  /* optional class for removing the outline */
29  .prism-editor__textarea:focus {
30    outline: none;
31  }
32</style>
33
34<div id="app">
35  <prism-editor class="my-editor height-200" v-model="code" :highlight="highlighter" line-numbers></prism-editor>
36</div>
37
38<script>
39  new Vue({
40    el: '#app',
41    data: () => ({
42      code: `BEGIN PGM NC100001A1 MM
43BLK FORM 0.1 Z X-31.5 Y-31.5 Z-44
44BLK FORM 0.2 X+281.5 Y+155 Z0
45;ARTIKELBEZ    : CAM-Konturen
46;LAUFZEIT      :
47;PROGRAMMIERER : Test Entwickler
48;DATUM         : 13.01.2020 09:23:20             
49;****************************
50;WERKZEUGE:
51* - T3=VHM_Fraeser_D20.00 D20 
52* - T2=EckMeko_D63_SPMT D63 
53* - T1=ISCAR_Eckfraeser_WPL_D20_APKT D20
54`,
55    }),
56    methods: {
57      highlighter(code) {
58        // js highlight example
59        return Prism.highlight(code, Prism.languages.js, 'gcode');
60      },
61    },
62  });
63</script>

Props

Name	Type	Default	Options	Description
v-model value	string	""	-	Current value of the editor i.e. the code to display
highlight	string => string	-	-	Callback which will receive text to highlight. You'll need to return an HTML string with syntax highlighting using a library such as prismjs.
readonly	Boolean	false	-	Readonly
lineNumbers	Boolean	false	-	Whether to show line numbers. Default false
autoStyleLineNumbers	Boolean	true	-	Match line numbers text color to the theme. Default true
tabSize	number	2	-	The number of characters to insert when pressing tab key. For example, for 4 space indentation, tabSize will be 4 and insertSpaces will be true. Default: 2
insertSpaces	boolean	true	-	Whether to use spaces for indentation. Default: true. If you set it to false, you might also want to set tabSize to 1
ignoreTabKey	boolean	false	-	Whether the editor should ignore tab key presses so that keyboard users can tab past the editor. Users can toggle this behaviour using Ctrl+Shift+M (Mac) / Ctrl+M manually when this is false. Default: false

Events

Name	Parameters	Description
input	(code)	Fires when the code is changed.
keydown	(event)	This event is emitted when a keydown event happens in editor
keyup	(event)	This event is emitted when a keyup event happens in editor
click	(event)	This event is emitted when clicking anywhere in the editor
focus	(event)	This event is emitted when focus
blur	(event)	This event is emitted when blur

How it works

It works by overlaying a syntax highlighted <pre> block over a <textarea>. When you type, select, copy text etc., you interact with the underlying <textarea>, so the experience feels native. This is a very simple approach compared to other editors which re-implement the behaviour.

The syntax highlighting can be done by any third party library as long as it returns HTML and is fully controllable by the user.

The vanilla <textarea> doesn't support inserting tab characters for indentation, so we re-implement it by listening to keydown events and programmatically updating the text. One caveat with programmatically updating the text is that we lose the undo stack, so we need to maintain our own undo stack. As a result, we can also implement improved undo behaviour such as undoing whole words similar to editors like VSCode.

Limitations

Due to the way it works, it has certain limitations:

• The syntax highlighted code cannot have different font family, font weight, font style, line height etc. for its content. Since the editor works by aligning the highlighted code over a <textarea>, changing anything that affects the layout can misalign it.
• The custom undo stack is incompatible with undo/redo items browser's context menu. However, other full featured editors don't support browser's undo/redo menu items either.
• The editor is not optimized for performance and large documents can affect the typing speed.
• We hide text in the textarea using -webkit-text-fill-color: transparent, which works in all modern browsers (even non-webkit ones such as Firefox and Edge). On IE 10+, we use color: transparent which doesn't hide the cursor. Text may appear bolder in unsupported browsers.