443 lines
12 KiB
JavaScript
443 lines
12 KiB
JavaScript
/**
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* @typedef {import('acorn').Comment} Comment
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* @typedef {import('acorn').Node} AcornNode
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* @typedef {import('acorn').Options} AcornOptions
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* @typedef {import('acorn').Token} Token
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* @typedef {import('estree').Node} EstreeNode
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* @typedef {import('estree').Program} Program
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* @typedef {import('micromark-util-types').Chunk} Chunk
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* @typedef {import('micromark-util-types').Event} Event
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* @typedef {import('micromark-util-types').Point} MicromarkPoint
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* @typedef {import('unist').Point} UnistPoint
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*/
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/**
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* @typedef Acorn
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* Acorn-like interface.
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* @property {import('acorn').parse} parse
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* Parse a program.
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* @property {import('acorn').parseExpressionAt} parseExpressionAt
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* Parse an expression.
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*
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* @typedef AcornLoc
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* @property {number} line
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* @property {number} column
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*
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* @typedef AcornErrorFields
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* @property {number} raisedAt
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* @property {number} pos
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* @property {AcornLoc} loc
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*
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* @typedef {Error & AcornErrorFields} AcornError
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*
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* @typedef Options
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* Configuration.
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* @property {Acorn} acorn
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* Typically `acorn`, object with `parse` and `parseExpressionAt` fields.
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* @property {AcornOptions | null | undefined} [acornOptions]
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* Configuration for `acorn`.
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* @property {MicromarkPoint | null | undefined} [start]
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* Place where events start.
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* @property {string | null | undefined} [prefix='']
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* Text to place before events.
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* @property {string | null | undefined} [suffix='']
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* Text to place after events.
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* @property {boolean | null | undefined} [expression=false]
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* Whether this is a program or expression.
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* @property {boolean | null | undefined} [allowEmpty=false]
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* Whether an empty expression is allowed (programs are always allowed to
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* be empty).
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*
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* @typedef Result
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* Result.
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* @property {Program | undefined} estree
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* Program.
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* @property {AcornError | undefined} error
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* Error if unparseable
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* @property {boolean} swallow
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* Whether the error, if there is one, can be swallowed and more JavaScript
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* could be valid.
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*
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* @typedef {[number, MicromarkPoint]} Stop
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*
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* @typedef Collection
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* @property {string} value
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* @property {Array<Stop>} stops
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*/
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import {visit} from 'estree-util-visit'
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import {VFileMessage} from 'vfile-message'
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/**
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* Parse a list of micromark events with acorn.
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*
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* @param {Array<Event>} events
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* Events.
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* @param {Options} options
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* Configuration.
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* @returns {Result}
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* Result.
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*/
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// eslint-disable-next-line complexity
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export function eventsToAcorn(events, options) {
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const prefix = options.prefix || ''
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const suffix = options.suffix || ''
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const acornOptions = Object.assign({}, options.acornOptions)
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/** @type {Array<Comment>} */
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const comments = []
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/** @type {Array<Token>} */
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const tokens = []
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const onComment = acornOptions.onComment
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const onToken = acornOptions.onToken
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let swallow = false
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/** @type {AcornNode | undefined} */
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let estree
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/** @type {AcornError | undefined} */
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let exception
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/** @type {AcornOptions} */
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const acornConfig = Object.assign({}, acornOptions, {
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onComment: comments,
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preserveParens: true
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})
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if (onToken) {
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acornConfig.onToken = tokens
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}
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const collection = collect(events, [
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'lineEnding',
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// To do: these should be passed by users in parameters.
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'expressionChunk',
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// From tests.
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'mdxFlowExpressionChunk',
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// Flow chunk.
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'mdxTextExpressionChunk',
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// Text chunk.
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// JSX:
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'mdxJsxTextTagExpressionAttributeValue',
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'mdxJsxTextTagAttributeValueExpressionValue',
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'mdxJsxFlowTagExpressionAttributeValue',
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'mdxJsxFlowTagAttributeValueExpressionValue',
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// ESM:
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'mdxjsEsmData'
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])
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const source = collection.value
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const value = prefix + source + suffix
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const isEmptyExpression = options.expression && empty(source)
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if (isEmptyExpression && !options.allowEmpty) {
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throw new VFileMessage(
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'Unexpected empty expression',
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parseOffsetToUnistPoint(0),
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'micromark-extension-mdx-expression:unexpected-empty-expression'
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)
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}
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try {
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estree =
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options.expression && !isEmptyExpression
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? options.acorn.parseExpressionAt(value, 0, acornConfig)
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: options.acorn.parse(value, acornConfig)
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} catch (error_) {
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const error = /** @type {AcornError} */ error_
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const point = parseOffsetToUnistPoint(error.pos)
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error.message = String(error.message).replace(/ \(\d+:\d+\)$/, '')
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// Always defined in our unist points that come from micromark.
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error.pos = point.offset
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error.loc = {
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line: point.line,
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column: point.column - 1
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}
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exception = error
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swallow =
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error.raisedAt >= prefix.length + source.length ||
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// Broken comments are raised at their start, not their end.
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error.message === 'Unterminated comment'
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}
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if (estree && options.expression && !isEmptyExpression) {
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if (empty(value.slice(estree.end, value.length - suffix.length))) {
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estree = {
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type: 'Program',
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start: 0,
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end: prefix.length + source.length,
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// @ts-expect-error: It’s good.
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body: [
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{
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type: 'ExpressionStatement',
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expression: estree,
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start: 0,
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end: prefix.length + source.length
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}
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],
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sourceType: 'module',
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comments: []
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}
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} else {
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const point = parseOffsetToUnistPoint(estree.end)
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const error =
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/** @type {AcornError} */
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new Error('Unexpected content after expression')
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// Always defined in our unist points that come from micromark.
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error.pos = point.offset
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error.loc = {
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line: point.line,
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column: point.column - 1
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}
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exception = error
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estree = undefined
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}
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}
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if (estree) {
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// @ts-expect-error: acorn *does* allow comments
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estree.comments = comments
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// @ts-expect-error: acorn looks enough like estree.
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visit(estree, (esnode, field, index, parents) => {
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let context =
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/** @type {AcornNode | Array<AcornNode>} */
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parents[parents.length - 1]
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/** @type {string | number | null} */
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let prop = field
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// Remove non-standard `ParenthesizedExpression`.
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// @ts-expect-error: included in acorn.
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if (esnode.type === 'ParenthesizedExpression' && context && prop) {
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/* c8 ignore next 5 */
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if (typeof index === 'number') {
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// @ts-expect-error: indexable.
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context = context[prop]
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prop = index
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}
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// @ts-expect-error: indexable.
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context[prop] = esnode.expression
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}
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fixPosition(esnode)
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})
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// Comment positions are fixed by `visit` because they’re in the tree.
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if (Array.isArray(onComment)) {
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onComment.push(...comments)
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} else if (typeof onComment === 'function') {
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for (const comment of comments) {
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onComment(
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comment.type === 'Block',
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comment.value,
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comment.start,
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comment.end,
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comment.loc.start,
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comment.loc.end
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)
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}
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}
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for (const token of tokens) {
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// Ignore tokens that ends in prefix or start in suffix:
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if (
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token.end <= prefix.length ||
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token.start - prefix.length >= source.length
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) {
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continue
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}
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fixPosition(token)
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if (Array.isArray(onToken)) {
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onToken.push(token)
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} else {
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// `tokens` are not added if `onToken` is not defined, so it must be a
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// function.
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onToken(token)
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}
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}
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}
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// @ts-expect-error: It’s a program now.
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return {
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estree,
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error: exception,
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swallow
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}
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/**
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* Update the position of a node.
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*
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* @param {AcornNode | EstreeNode | Token} nodeOrToken
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* @returns {void}
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*/
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function fixPosition(nodeOrToken) {
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const pointStart = parseOffsetToUnistPoint(nodeOrToken.start)
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const pointEnd = parseOffsetToUnistPoint(nodeOrToken.end)
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// Always defined in our unist points that come from micromark.
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nodeOrToken.start = pointStart.offset
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nodeOrToken.end = pointEnd.offset
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nodeOrToken.loc = {
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start: {
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line: pointStart.line,
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column: pointStart.column - 1,
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offset: pointStart.offset
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},
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end: {
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line: pointEnd.line,
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column: pointEnd.column - 1,
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offset: pointEnd.offset
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}
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}
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nodeOrToken.range = [nodeOrToken.start, nodeOrToken.end]
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}
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/**
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* Turn an arbitrary offset into the parsed value, into a point in the source
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* value.
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*
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* @param {number} acornOffset
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* @returns {UnistPoint}
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*/
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function parseOffsetToUnistPoint(acornOffset) {
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let sourceOffset = acornOffset - prefix.length
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if (sourceOffset < 0) {
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sourceOffset = 0
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} else if (sourceOffset > source.length) {
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sourceOffset = source.length
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}
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let point = relativeToPoint(collection.stops, sourceOffset)
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if (!point) {
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point = {
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line: options.start.line,
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column: options.start.column,
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offset: options.start.offset
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}
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}
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return point
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}
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}
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/**
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* @param {string} value
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* @returns {boolean}
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*/
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function empty(value) {
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return /^\s*$/.test(
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value
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// Multiline comments.
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.replace(/\/\*[\s\S]*?\*\//g, '')
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// Line comments.
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// EOF instead of EOL is specifically not allowed, because that would
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// mean the closing brace is on the commented-out line
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.replace(/\/\/[^\r\n]*(\r\n|\n|\r)/g, '')
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)
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}
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// Port from <https://github.com/wooorm/markdown-rs/blob/e692ab0/src/util/mdx_collect.rs#L15>.
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/**
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* @param {Array<Event>} events
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* @param {Array<string>} names
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* @returns {Collection}
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*/
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function collect(events, names) {
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/** @type {Collection} */
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const result = {
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value: '',
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stops: []
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}
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let index = -1
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while (++index < events.length) {
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const event = events[index]
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// Assume void.
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if (event[0] === 'enter' && names.includes(event[1].type)) {
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const chunks = event[2].sliceStream(event[1])
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// Drop virtual spaces.
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while (chunks.length > 0 && chunks[0] === -1) {
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chunks.shift()
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}
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const value = serializeChunks(chunks)
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result.stops.push([result.value.length, event[1].start])
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result.value += value
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result.stops.push([result.value.length, event[1].end])
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}
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}
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return result
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}
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// Port from <https://github.com/wooorm/markdown-rs/blob/e692ab0/src/util/location.rs#L91>.
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/**
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* Turn a relative offset into an absolute offset.
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*
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* @param {Array<Stop>} stops
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* @param {number} relative
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* @returns {UnistPoint | undefined}
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*/
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function relativeToPoint(stops, relative) {
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let index = 0
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while (index < stops.length && stops[index][0] <= relative) {
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index += 1
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}
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// There are no points: that only occurs if there was an empty string.
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if (index === 0) {
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return undefined
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}
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const [stopRelative, stopAbsolute] = stops[index - 1]
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const rest = relative - stopRelative
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return {
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line: stopAbsolute.line,
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column: stopAbsolute.column + rest,
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offset: stopAbsolute.offset + rest
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}
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}
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// Copy from <https://github.com/micromark/micromark/blob/ce3593a/packages/micromark/dev/lib/create-tokenizer.js#L595>
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// To do: expose that?
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/**
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* Get the string value of a slice of chunks.
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*
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* @param {Array<Chunk>} chunks
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* @returns {string}
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*/
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function serializeChunks(chunks) {
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let index = -1
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/** @type {Array<string>} */
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const result = []
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/** @type {boolean | undefined} */
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let atTab
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while (++index < chunks.length) {
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const chunk = chunks[index]
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/** @type {string} */
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let value
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if (typeof chunk === 'string') {
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value = chunk
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} else
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switch (chunk) {
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case -5: {
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value = '\r'
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break
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}
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case -4: {
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value = '\n'
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break
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}
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case -3: {
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value = '\r' + '\n'
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break
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}
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case -2: {
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value = '\t'
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break
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}
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/* c8 ignore next 6 */
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case -1: {
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if (atTab) continue
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value = ' '
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break
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}
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default: {
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// Currently only replacement character.
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// eslint-disable-next-line unicorn/prefer-code-point
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value = String.fromCharCode(chunk)
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}
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}
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atTab = chunk === -2
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result.push(value)
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}
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return result.join('')
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}
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