37 lines
1.1 KiB
JavaScript
37 lines
1.1 KiB
JavaScript
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/**
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* Turn the number (in string form as either hexa- or plain decimal) coming from
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* a numeric character reference into a character.
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*
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* Sort of like `String.fromCharCode(Number.parseInt(value, base))`, but makes
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* non-characters and control characters safe.
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*
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* @param {string} value
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* Value to decode.
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* @param {number} base
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* Numeric base.
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* @returns {string}
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* Character.
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*/
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export function decodeNumericCharacterReference(value, base) {
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const code = Number.parseInt(value, base)
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if (
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// C0 except for HT, LF, FF, CR, space.
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code < 9 ||
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code === 11 ||
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(code > 13 && code < 32) ||
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// Control character (DEL) of C0, and C1 controls.
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(code > 126 && code < 160) ||
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// Lone high surrogates and low surrogates.
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(code > 55295 && code < 57344) ||
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// Noncharacters.
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(code > 64975 && code < 65008) /* eslint-disable no-bitwise */ ||
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(code & 65535) === 65535 ||
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(code & 65535) === 65534 /* eslint-enable no-bitwise */ ||
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// Out of range
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code > 1114111
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) {
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return '\uFFFD'
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}
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return String.fromCharCode(code)
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}
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