49 lines
1.9 KiB
TypeScript
49 lines
1.9 KiB
TypeScript
export type LinePosition = 'first' | 'later'
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const controlCharacterRange = '\\u0000-\\u001f\\u007f'
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const autolinkSource = `[A-Za-z][A-Za-z0-9+.-]{1,31}:[^\\s<>${controlCharacterRange}]*`
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const entityReferenceSource = '&(?:[A-Za-z][A-Za-z0-9]{1,31}|#\\d{1,7}|#[Xx][A-Fa-f0-9]{1,6});'
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const anchoredEntityReference = new RegExp(`^(?:${entityReferenceSource})`)
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const autolink = new RegExp(`^(?:${autolinkSource})$`)
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const bracketedAutolink = new RegExp(`^<(?:${autolinkSource})>`)
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const controlCharacter = new RegExp(`[${controlCharacterRange}]`)
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const entityReference = new RegExp(entityReferenceSource)
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const firstCharacterOpeners = [/^#{1,6}(?:[ \t]|$)/, /^>/, /^[*+-](?:[ \t]|$)/, /^`{3,}/, /^~{3,}/, /^:{2,}/, /^\|/]
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const orderedListOpener = /^(\d{1,9})[.)](?:[ \t]|$)/
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const setextUnderline = /^=+$/
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const thematicBreak = /^(?:(?:\*[ \t]*){3,}|(?:-[ \t]*){3,}|(?:_[ \t]*){3,})$/
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export function claimsLine(line: string, position: LinePosition): boolean {
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return escapesLineClaim(line, 0, position) || orderedListOpener.test(line)
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}
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export function escapesLineClaim(line: string, offset: number, position: LinePosition): boolean {
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if (offset === 0) {
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if (firstCharacterOpeners.some((opener) => opener.test(line)) || thematicBreak.test(line)) return true
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return position === 'later' && setextUnderline.test(line)
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}
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const digits = orderedListOpener.exec(line)?.[1]
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return digits !== undefined && offset === digits.length
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}
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export function holdsControlCharacter(text: string): boolean {
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return controlCharacter.test(text)
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}
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export function holdsEntityReference(text: string): boolean {
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return entityReference.test(text)
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}
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export function isAutolink(text: string): boolean {
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return autolink.test(text)
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}
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export function opensBracketedAutolink(text: string): boolean {
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return bracketedAutolink.test(text)
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}
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export function startsEntityReference(text: string): boolean {
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return anchoredEntityReference.test(text)
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}
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