54 lines
1.4 KiB
Plaintext
54 lines
1.4 KiB
Plaintext
import {decodeNamedCharacterReference} from 'decode-named-character-reference'
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import {decodeNumericCharacterReference} from 'micromark-util-decode-numeric-character-reference'
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import {codes, constants} from 'micromark-util-symbol'
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const characterEscapeOrReference =
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/\\([!-/:-@[-`{-~])|&(#(?:\d{1,7}|x[\da-f]{1,6})|[\da-z]{1,31});/gi
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/**
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* Decode markdown strings (which occur in places such as fenced code info
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* strings, destinations, labels, and titles).
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*
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* The “string” content type allows character escapes and -references.
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* This decodes those.
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*
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* @param {string} value
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* Value to decode.
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* @returns {string}
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* Decoded value.
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*/
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export function decodeString(value) {
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return value.replace(characterEscapeOrReference, decode)
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}
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/**
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* @param {string} $0
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* Match.
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* @param {string} $1
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* Character escape.
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* @param {string} $2
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* Character reference.
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* @returns {string}
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* Decoded value
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*/
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function decode($0, $1, $2) {
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if ($1) {
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// Escape.
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return $1
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}
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// Reference.
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const head = $2.charCodeAt(0)
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if (head === codes.numberSign) {
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const head = $2.charCodeAt(1)
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const hex = head === codes.lowercaseX || head === codes.uppercaseX
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return decodeNumericCharacterReference(
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$2.slice(hex ? 2 : 1),
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hex ? constants.numericBaseHexadecimal : constants.numericBaseDecimal
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)
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}
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return decodeNamedCharacterReference($2) || $0
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}
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