37 lines
1.2 KiB
Plaintext
37 lines
1.2 KiB
Plaintext
/// <reference lib="dom" />
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/* global document */
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const element = document.createElement('i')
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/**
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* @param {string} value
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* @returns {string | false}
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*/
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export function decodeNamedCharacterReference(value) {
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const characterReference = '&' + value + ';'
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element.innerHTML = characterReference
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const character = element.textContent
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// Some named character references do not require the closing semicolon
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// (`¬`, for instance), which leads to situations where parsing the assumed
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// named reference of `¬it;` will result in the string `¬it;`.
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// When we encounter a trailing semicolon after parsing, and the character
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// reference to decode was not a semicolon (`;`), we can assume that the
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// matching was not complete.
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if (
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// @ts-expect-error: TypeScript is wrong that `textContent` on elements can
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// yield `null`.
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character.charCodeAt(character.length - 1) === 59 /* `;` */ &&
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value !== 'semi'
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) {
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return false
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}
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// If the decoded string is equal to the input, the character reference was
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// not valid.
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// @ts-expect-error: TypeScript is wrong that `textContent` on elements can
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// yield `null`.
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return character === characterReference ? false : character
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}
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