Registry / serialization / micromark-util-character

micromark-util-character

library2.1.1jsnpmunverified

micromark-util-character is a utility package within the micromark ecosystem, providing a collection of pure functions to efficiently check whether a given character code belongs to various predefined groups, such as ASCII alphanumeric, punctuation, or Markdown-specific line endings and spaces. It is currently at version 2.1.1. As part of the larger micromark project, its release cadence is tied to the main project's development. This package is crucial for developers building custom micromark extensions or parsers who need granular control and performant character classification, differentiating itself by offering a specialized, low-level API for fundamental parsing operations rather than general-purpose string manipulation.

serialization

npm install micromark-util-character

github ↗package ↗

INSTALL

IMPORT

SIG · MICROMARK-UTIL-CHA

micromark-util-character

serializationjavascriptv2.1.1

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

asciiAlpha

✓ import { asciiAlpha } from 'micromark-util-character'

✗ const { asciiAlpha } = require('micromark-util-character')

micromark-util-character is an ESM-only package since v1. Named imports are required as there is no default export.

markdownLineEnding

✓ import { markdownLineEnding } from 'micromark-util-character'

✗ import markdownLineEnding from 'micromark-util-character'

Only named exports are available; there is no default export from this module.

unicodeWhitespace

✓ import { unicodeWhitespace } from 'micromark-util-character'

✗ const unicodeWhitespace = require('micromark-util-character').unicodeWhitespace

Ensure you are using named imports for ESM modules. Direct property access on a require result will fail.

This quickstart demonstrates how to use several utility functions to check character codes for various properties, such as being an ASCII alpha, Markdown line ending, or Unicode punctuation. It also shows a simple custom function combining these utilities.

import { asciiAlpha, markdownLineEnding, unicodePunctuation, asciiDigit } from 'micromark-util-character'; console.log('--- Character Checks ---'); const charA = 65; // 'A' const charNewline = 10; // '\n' const charAmpersand = 38; // '&' const charDigit = 50; // '2' const charSpace = 32; // ' ' const charUnicodePunctuation = 8212; // '—' (em dash) console.log(`Is '${String.fromCharCode(charA)}' an ASCII alpha character? ${asciiAlpha(charA)}`); console.log(`Is '${String.fromCharCode(charNewline)}' a Markdown line ending? ${markdownLineEnding(charNewline)}`); console.log(`Is '${String.fromCharCode(charAmpersand)}' a Unicode punctuation character? ${unicodePunctuation(charAmpersand)}`); console.log(`Is '${String.fromCharCode(charDigit)}' an ASCII digit character? ${asciiDigit(charDigit)}`); console.log(`Is '${String.fromCharCode(charSpace)}' a Markdown space? ${markdownLineEnding(charSpace)}`); console.log(`Is '${String.fromCharCode(charUnicodePunctuation)}' a Unicode punctuation character? ${unicodePunctuation(charUnicodePunctuation)}`); // Demonstrating a common pattern for custom parsers: function isStartOfWord(code) { return asciiAlpha(code) || asciiDigit(code); } const testCode = 'H'.charCodeAt(0); console.log(`Is '${String.fromCharCode(testCode)}' a start of word? ${isStartOfWord(testCode)}`);

Debug

Known issues

breakingThe package transitioned to being ESM-only. CommonJS `require()` statements will no longer work and will result in errors.

fix

Migrate your import statements to use ES modules syntax: `import { functionName } from 'micromark-util-character'`.

affects: >=1.0.0

breakingVersion 2.1.0 included updates for 'CM 0.31' and added Unicode symbols for attention. While not explicitly detailed as breaking, changes related to character attention and CommonMark versions can subtly alter parsing behavior if custom extensions relied on previous interpretations.

fix

Review any custom micromark extensions that interact closely with character classification, especially for Unicode characters or 'attention' mechanisms, and test thoroughly with the new version.

affects: >=2.1.0

gotchaThe utility functions expect character *codes* (numbers), not character *strings*. Passing a string will result in incorrect behavior or runtime errors.

fix

Always convert characters to their code points using `String.prototype.charCodeAt(0)` before passing them to these utility functions.

affects: >=1.0.0

gotchaBe mindful of the distinction between 'ASCII' and 'Unicode' prefixed functions. Functions like `asciiAlpha` only check within the ASCII range, while `unicodePunctuation` and `unicodeWhitespace` handle a broader set of characters. Using an ASCII-only check for non-ASCII input will yield false results.

fix

Choose the appropriate utility function based on the character set you intend to handle. For broader internationalization, prefer `unicode*` checks where available or implement custom logic.

affects: >=1.0.0

Errors

Common errors & fixes

ERR_REQUIRE_ESM

Attempting to import an ESM-only package using CommonJS `require()` syntax.

fix

Change `const { asciiAlpha } = require('micromark-util-character')` to `import { asciiAlpha } from 'micromark-util-character'`.

TypeError: Cannot read properties of undefined (reading 'charCodeAt')

Passing `null` or `undefined` as a character code to a utility function.

fix

Ensure the input to character utility functions is always a valid number representing a character code. Add checks for `null` or `undefined` if the source of the code is untrustworthy.

Property 'asciiAlpha' does not exist on type 'typeof import("micromark-util-character")'.

Attempting to use a non-existent export or incorrect named import for a utility function.

fix

Verify the exact name of the imported function and ensure it is correctly destructured from the named exports, e.g., `import { asciiAlpha } from 'micromark-util-character'`.

Upgrade

Version history

2.1.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/micromark/micromark.git#main ↗

packagehttps://www.npmjs.com/package/micromark-util-character ↗