Svelte Code Input

Svelte Code Input is a small component for SvelteJS that allows you to create a lightweight text area component which will automatically syntax highlight the code you type in it. It is designed for basic use cases where you want to display code to the user, and allow them to edit it, without all the overhead of a full blown code editor.

final-svelte.mp4

It supports both PrismJS and HighlightJS to do the syntax highlighting, and will use either depending on which library you pass in as a prop.

Features

• Very Lightweight
• Easier to use than CodeMirror, Ace, and Monaco
• Supports both PrismJS and HighlightJS
• Auto Indentation
• Tab to indent
• Auto resize to fit content
• Resizable
• Placeholders

Installation

npm install @srsholmes/svelte-code-input
# or
yarn add @srsholmes/svelte-code-input

Usage

import CodeInput from '@srsholmes/svelte-code-input/CodeInput.svelte';

<CodeInput
  autoHeight={true}
  resize="both"
  placeholder="Input your code here..."
  prismJS={Prism}
  onChange={setInput}
  value={'const hello = "world";'}
  language={'typescript'}
/>;

API

CodeInput takes the following props:

Name	Type	Description
prismJS	typeof Prism	Optional. An instance of the Prism library for syntax highlighting.
highlightjs	typeof highlightjs	Optional. An instance of the Highlight.js library for syntax highlighting.
value	string	Required. The value of the code input.
language	string	Required. The language of the code input.
onChange	(value: string) => void	Required. A callback function that is called when the value of the input changes.
placeholder	string	Optional. Placeholder text for the input.
resize	'both' | 'horizontal' | 'vertical'	Optional. Specifies whether the input can be resized, and in which direction.
autoHeight	boolean	Optional. Specifies whether the input height should adjust automatically.

Types

export type CodeInputProps = {
  prismJS?: typeof Prism;
  highlightjs?: typeof highlightjs;
  value: string;
  language: string;
  onChange: (value: string) => void;
  placeholder?: string;
  resize?: 'both' | 'horizontal' | 'vertical';
  autoHeight?: boolean;
};

Example App

To run the example app, clone the repo and run the following commands:

git clone https://github.com/srsholmes/svelte-code-input
yarn # Install dependencies
yarn dev

Shout outs

Shout out to Oliver Geer (WebCoder49) for this awesome article which inspired this component Creating an Editable Textarea That Supports Syntax-Highlighted Code.

The method used was heavily inspired by this repo code-input, and the auto indent was taken directly from his indent plugin.

License

MIT