content-tag

content-tag is a preprocessor for JS files that are using the content-tag proposal. This originated with Ember.js' GJS and GTS functionality. You can read more by checking out the original RFC

This preprocessor can be used to transform files using the content-tag spec to standard JS. It is built on top of swc using Rust and is deployed as a wasm package.

Installation

npm install content-tag

Usage

Node (CommonJS)

let { Preprocessor } = require('content-tag');
let p = new Preprocessor();
let output = p.process('<template>Hi</template>');

console.log(output);

Node (ESM)

import { Preprocessor } from 'content-tag';
let p = new Preprocessor();
let output = p.process('<template>Hi</template>');

console.log(output);

Browser (ESM)

import { Preprocessor } from 'content-tag';
let p = new Preprocessor();
let output = p.process('<template>Hi</template>');

console.log(output);

API

Preprocessor

All content-tag public API lives on the Preprocessor object.

Preprocessor.process(src: string, options?: PreprocessorOptions): string;

Parses a given source code string using the content-tag spec into standard JavaScript.

import { Preprocessor } from 'content-tag';
let p = new Preprocessor();
let output = p.process('<template>Hi</template>');

Preprocessor.parse(src: string, options?: PreprocessorOptions): Parsed[];

Parses a given source code string using the content-tag spec into an array of Parsed content tag objects.

import { Preprocessor } from 'content-tag';
let p = new Preprocessor();
let output = p.parse('<template>Hi</template>');

PreprocessorOptions

interface PreprocessorOptions {

  /** Default is `false` */
  inline_source_map?: boolean;

  filename?: string;

}

Parsed

NOTE: All ranges are in bytes, not characters.

interface Parsed {
  /**
   * The type for the content tag.
   *
   * 'expression' corresponds to a tag in an expression position, e.g.
   * ```
   * const HiComponent = <template>Hi</template>;
   * ```
   *
   * 'class-member' corresponds to a tag in a class-member position, e.g.
   * ```
   * export default class HiComponent extends Component {
   *   <template>Hi</template>
   * }
   * ```
   */
  type: "expression" | "class-member";

  /**
   * Currently, only template tags are parsed.
   */
  tagName: "template";

  /** Raw template contents. */
  contents: string;

  /**
   * Byte range of the contents, inclusive of inclusive of the
   * `<template></template>` tags.
   */
  range: {
    start: number;
    end: number;
  };

  /**
   * Byte range of the template contents, not inclusive of the
   * `<template></template>` tags.
   */
  contentRange: {
    start: number;
    end: number;
  };

  /** Byte range of the opening `<template>` tag. */
  startRange: {
    end: number;
    start: number;
  };

  /** Byte range of the closing `</template>` tag. */
  endRange: {
    start: number;
    end: number;
  };
}

Contributing

See the CONTRIBUTING.md file.