Registry / testing / mdast-util-assert

mdast-util-assert

library5.0.0jsnpmunverified

mdast-util-assert is a focused utility from the unified collective designed to validate the structure and properties of mdast (Markdown Abstract Syntax Tree) nodes. It provides functions to assert that a given object conforms to the expected shape of mdast nodes, including parent, literal, and void nodes. This package is particularly useful within API contexts where specific node types are expected, ensuring data integrity and preventing unexpected runtime errors. The current stable version is 5.0.0, which requires Node.js 16+ and is exclusively an ES Module (ESM). Release cadence generally follows semver, with major versions introducing breaking changes related to Node.js compatibility or module systems, while minor versions address bug fixes and documentation. Its key differentiator is its specialization for mdast nodes, building upon and re-exporting parts of the more general `unist-util-assert` for universal syntax trees.

testing

npm install mdast-util-assert

github ↗package ↗

INSTALL

IMPORT

SIG · MDAST-UTIL-ASSERT

mdast-util-assert

testingjavascriptv5.0.0

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.

assert

✓ import { assert } from 'mdast-util-assert'

✗ const assert = require('mdast-util-assert').assert

ESM-only since v4; CommonJS 'require' is not supported.

parent

✓ import { parent } from 'mdast-util-assert'

✗ const parent = require('mdast-util-assert').parent

ESM-only since v4. This specific assertion validates parent nodes and their children.

AssertionError

✓ import { AssertionError } from 'mdast-util-assert'

✗ const AssertionError = require('mdast-util-assert').AssertionError

ESM-only since v4. This error class is thrown when an assertion fails. It's re-exported from `unist-util-assert`.

literal

✓ import { literal } from 'mdast-util-assert'

✗ const literal = require('mdast-util-assert').literal

ESM-only since v4. Use this to assert that a node is an mdast Literal node.

Demonstrates how to use `assert` to validate mdast nodes, showing successful and failing assertions with error handling.

import { assert } from 'mdast-util-assert' // Assert valid mdast nodes assert({type: 'root', children: []}) assert({type: 'break'}) assert({type: 'listItem', checked: true, children: []}) // This will throw an AssertionError due to missing 'type' property try { assert({children: []}) } catch (error) { console.error(error.message) // AssertionError: node should have a type: `{ children: [] }` } // This will throw an AssertionError due to incorrect property for a 'paragraph' node try { assert({type: 'paragraph', value: 'foo'}) } catch (error) { console.error(error.message) // AssertionError: parent should have children: `{ type: 'paragraph', value: 'foo' }` }

Debug

Known issues

breakingVersion 5.0.0 and above require Node.js 16 or higher due to ecosystem-wide updates.

fix

Upgrade your Node.js environment to version 16 or later to use `mdast-util-assert@5`.

affects: >=5.0.0

breakingThe package became ESM-only (ECMAScript Modules) starting from v4, and v5 solidifies this with an 'exports' map. CommonJS 'require()' is no longer supported directly.

fix

Migrate your project to use ES Modules (import/export syntax). If you are unable to migrate, you might need to pin to a version below 4.0.0 or use dynamic `import()` for ESM-only packages.

affects: >=4.0.0

breakingUpgrading to version 5.0.0 may require updating your `@types/mdast` dependency to ensure compatibility with the latest type definitions.

fix

Update `@types/mdast` to the latest compatible version (`npm install @types/mdast@latest`).

affects: >=5.0.0

breakingVersion 3.0.0 introduced significant TypeScript implications. If you or your dependents were using TypeScript but not explicitly expecting type enforcement, this could cause type errors.

fix

Review and update your TypeScript configurations and type usage to align with the type definitions introduced in v3.

affects: >=3.0.0 <4.0.0

Errors

Common errors & fixes

AssertionError: node should have a type: { children: [] }

Attempting to assert a node object that is missing the mandatory `type` property.

fix

Ensure all mdast nodes passed to assertion functions have a `type` property, for example: `{ type: 'root', children: [] }`.

AssertionError: parent should have children: { type: 'paragraph', value: 'foo' }

Attempting to assert a `Parent` node (like `paragraph`) with a `value` property instead of `children`.

fix

Correct the node structure. Parent nodes should have a `children` array property, while `Literal` nodes have a `value` property.

Error [ERR_REQUIRE_ESM]: require() of ES Module ...mdast-util-assert.js not supported.

Attempting to import the package using CommonJS `require()` syntax in a Node.js environment.

fix

This package is ESM-only since v4. Migrate your code to use `import` statements (e.g., `import { assert } from 'mdast-util-assert';`) and ensure your project is configured for ESM.

Upgrade

Version history

5.0.0latest on npm

Audit

Dependencies

unist-util-assertrequiredRe-exports assertion functions like `_void`, `wrap`, and `AssertionError` from this package for core assertion logic.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/syntax-tree/mdast-util-assert ↗

packagehttps://www.npmjs.com/package/mdast-util-assert ↗