wooorm / parse-entities

Parse HTML character references

parse-entities

Parse HTML character references.

Contents

• What is this?
• When should I use this?
• Install
• Use
• API
  • parseEntities(value[, options])
• Types
• Compatibility
• Security
• Related
• Contribute
• License

What is this?

This is a small and powerful decoder of HTML character references (often called entities).

When should I use this?

You can use this for spec-compliant decoding of character references. It’s small and fast enough to do that well. You can also use this when making a linter, because there are different warnings emitted with reasons for why and positional info on where they happened.

Install

This package is ESM only. In Node.js (version 14.14+, 16.0+), install with npm:

npm install parse-entities

In Deno with esm.sh:

import {parseEntities} from 'https://esm.sh/parse-entities@3'

In browsers with esm.sh:

<script type="module">
  import {parseEntities} from 'https://esm.sh/parse-entities@3?bundle'
</script>

Use

import {parseEntities} from 'parse-entities'

console.log(parseEntities('alpha &amp bravo')))
// => alpha & bravo

console.log(parseEntities('charlie &copycat; delta'))
// => charlie ©cat; delta

console.log(parseEntities('echo © foxtrot ≠ golf 𝌆 hotel'))
// => echo © foxtrot ≠ golf 𝌆 hotel

API

This package exports the identifier parseEntities. There is no default export.

parseEntities(value[, options])

Parse HTML character references.

options

Configuration (optional).

options.additional

Additional character to accept (string?, default: ''). This allows other characters, without error, when following an ampersand.

options.attribute

Whether to parse value as an attribute value (boolean?, default: false). This results in slightly different behavior.

options.nonTerminated

Whether to allow nonterminated references (boolean, default: true). For example, &copycat for ©cat. This behavior is compliant to the spec but can lead to unexpected results.

options.position

Starting position of value (Position or Point, optional). Useful when dealing with values nested in some sort of syntax tree. The default is:

{line: 1, column: 1, offset: 0}

options.warning

Error handler (Function?).

options.text

Text handler (Function?).

options.reference

Reference handler (Function?).

options.warningContext

Context used when calling warning ('*', optional).

options.textContext

Context used when calling text ('*', optional).

options.referenceContext

Context used when calling reference ('*', optional)

Returns

string — decoded value.

function warning(reason, point, code)

Error handler.

Parameters

• this (*) — refers to warningContext when given to parseEntities
• reason (string) — human readable reason for emitting a parse error
• point (Point) — place where the error occurred
• code (number) — machine readable code the error

The following codes are used:

Code	Example	Note
1	foo &amp bar	Missing semicolon (named)
2	foo &#123 bar	Missing semicolon (numeric)
3	Foo &bar baz	Empty (named)
4	Foo &#	Empty (numeric)
5	Foo &bar; baz	Unknown (named)
6	Foo € baz	Disallowed reference
7	Foo � baz	Prohibited: outside permissible unicode range

function text(value, position)

Text handler.

Parameters

• this (*) — refers to textContext when given to parseEntities
• value (string) — string of content
• position (Position) — place where value starts and ends

function reference(value, position, source)

Character reference handler.

Parameters

• this (*) — refers to referenceContext when given to parseEntities
• value (string) — decoded character reference
• position (Position) — place where source starts and ends
• source (string) — raw source of character reference

Types

This package is fully typed with TypeScript. It exports the additional types Options, WarningHandler, ReferenceHandler, and TextHandler.

Compatibility

This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. It also works in Deno and modern browsers.

Security

This package is safe: it matches the HTML spec to parse character references.

Related

• wooorm/stringify-entities — encode HTML character references
• wooorm/character-entities — info on character references
• wooorm/character-entities-html4 — info on HTML4 character references
• wooorm/character-entities-legacy — info on legacy character references
• wooorm/character-reference-invalid — info on invalid numeric character references

Contribute

Yes please! See How to Contribute to Open Source.

License

MIT © Titus Wormer