micromark Extension Combiner Utility

Common errors

• ERR_REQUIRE_ESM

  cause Attempting to import `micromark-util-combine-extensions` using CommonJS `require()` syntax in a Node.js environment.
  fix Change your import statement to `import { combineExtensions } from 'micromark-util-combine-extensions'`.

• TypeError: (0 , micromark_util_combine_extensions__WEBPACK_IMPORTED_MODULE_0__.combineExtensions) is not a function

  cause This error often occurs when bundling (e.g., with Webpack) and attempting to use a CommonJS-style import on an ESM module, or when a named import is incorrectly treated as a default import.
  fix Ensure your build configuration correctly handles ESM modules. Verify that you are using a named import `import { combineExtensions }` and not a default import `import combineExtensions`.

• TypeError: micromark_extension_gfm_strikethrough_1.gfmStrikethrough is not a function

  cause An extension function (like `gfmStrikethrough`) was expected to be called to produce an extension object, but it was passed directly without invocation.
  fix Call the extension as a function: `gfmStrikethrough()` instead of `gfmStrikethrough` when adding it to the array for `combineExtensions`.

Warnings

• breaking This package is ESM-only and does not support CommonJS `require()`. Attempting to import it with `require` will result in an error.
  Fix: Migrate your project to use ES modules (`import`) or use a build tool like Rollup or Webpack to handle ESM imports in a CommonJS context.
• gotcha This utility is designed to work with `micromark@3`. Using it with incompatible major versions of `micromark` (e.g., `micromark@2` or `micromark@4`) may lead to unexpected behavior or type mismatches due to changes in the extension object structure.
  Fix: Ensure your project explicitly lists `micromark@3` as a dependency or peer dependency and that your installed version matches this requirement.
• gotcha Some micromark extensions are exported as functions that need to be called (e.g., `gfmStrikethrough()`), while others are direct objects (e.g., `gfmAutolinkLiteral`). Not calling the function for extensions that expect it will result in an invalid extension being passed to `combineExtensions`.
  Fix: Always refer to the documentation for each individual micromark extension to confirm whether it needs to be called as a function or passed directly as an object.

Install

• npm install micromark-util-combine-extensions npm
• yarn add micromark-util-combine-extensions yarn
• pnpm add micromark-util-combine-extensions pnpm

Imports

• combineExtensions
  wrong:

  const { combineExtensions } = require('micromark-util-combine-extensions')

  correct:

  import { combineExtensions } from 'micromark-util-combine-extensions'

  This package is ESM-only, meaning CommonJS `require` syntax is not supported. Use ES modules `import`.
• combineHtmlExtensions
  wrong:

  import combineHtmlExtensions from 'micromark-util-combine-extensions'

  correct:

  import { combineHtmlExtensions } from 'micromark-util-combine-extensions'

  There is no default export; `combineHtmlExtensions` must be imported by name as a named export.

Quickstart

Demonstrates how to combine multiple individual micromark syntax extensions into a single extension object using `combineExtensions` for easier management and use with the `micromark` parser.

import {gfmAutolinkLiteral} from 'micromark-extension-gfm-autolink-literal'
import {gfmStrikethrough} from 'micromark-extension-gfm-strikethrough'
import {gfmTable} from 'micromark-extension-gfm-table'
import {gfmTaskListItem} from 'micromark-extension-gfm-task-list-item'
import {combineExtensions} from 'micromark-util-combine-extensions'

// This example combines several GFM syntax extensions into a single extension object
// suitable for use with micromark. Note that some extensions are functions that need
// to be called (e.g., gfmStrikethrough()), while others are direct objects.
const combinedGfmSyntaxExtension = combineExtensions([
  gfmAutolinkLiteral,
  gfmStrikethrough(), // Some extensions are functions that return the actual extension object
  gfmTable,
  gfmTaskListItem
])

console.log('Successfully combined GFM syntax extensions for micromark:', combinedGfmSyntaxExtension)

// You would typically pass this combined extension to the micromark parser:
// import { micromark } from 'micromark';
// const html = micromark('~Hello~', { extensions: [combinedGfmSyntaxExtension] });
// console.log(html); // Outputs HTML for strikethrough content, e.g., <p><del>Hello</del></p>