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- 'use strict'
- const INDENT = Symbol.for('indent')
- const NEWLINE = Symbol.for('newline')
- const DEFAULT_NEWLINE = '\n'
- const DEFAULT_INDENT = ' '
- const BOM = /^\uFEFF/
- // only respect indentation if we got a line break, otherwise squash it
- // things other than objects and arrays aren't indented, so ignore those
- // Important: in both of these regexps, the $1 capture group is the newline
- // or undefined, and the $2 capture group is the indent, or undefined.
- const FORMAT = /^\s*[{[]((?:\r?\n)+)([\s\t]*)/
- const EMPTY = /^(?:\{\}|\[\])((?:\r?\n)+)?$/
- // Node 20 puts single quotes around the token and a comma after it
- const UNEXPECTED_TOKEN = /^Unexpected token '?(.)'?(,)? /i
- const hexify = (char) => {
- const h = char.charCodeAt(0).toString(16).toUpperCase()
- return `0x${h.length % 2 ? '0' : ''}${h}`
- }
- // Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
- // because the buffer-to-string conversion in `fs.readFileSync()`
- // translates it to FEFF, the UTF-16 BOM.
- const stripBOM = (txt) => String(txt).replace(BOM, '')
- const makeParsedError = (msg, parsing, position = 0) => ({
- message: `${msg} while parsing ${parsing}`,
- position,
- })
- const parseError = (e, txt, context = 20) => {
- let msg = e.message
- if (!txt) {
- return makeParsedError(msg, 'empty string')
- }
- const badTokenMatch = msg.match(UNEXPECTED_TOKEN)
- const badIndexMatch = msg.match(/ position\s+(\d+)/i)
- if (badTokenMatch) {
- msg = msg.replace(
- UNEXPECTED_TOKEN,
- `Unexpected token ${JSON.stringify(badTokenMatch[1])} (${hexify(badTokenMatch[1])})$2 `
- )
- }
- let errIdx
- if (badIndexMatch) {
- errIdx = +badIndexMatch[1]
- } else /* istanbul ignore next - doesnt happen in Node 22 */ if (
- msg.match(/^Unexpected end of JSON.*/i)
- ) {
- errIdx = txt.length - 1
- }
- if (errIdx == null) {
- return makeParsedError(msg, `'${txt.slice(0, context * 2)}'`)
- }
- const start = errIdx <= context ? 0 : errIdx - context
- const end = errIdx + context >= txt.length ? txt.length : errIdx + context
- const slice = `${start ? '...' : ''}${txt.slice(start, end)}${end === txt.length ? '' : '...'}`
- return makeParsedError(
- msg,
- `${txt === slice ? '' : 'near '}${JSON.stringify(slice)}`,
- errIdx
- )
- }
- class JSONParseError extends SyntaxError {
- constructor (er, txt, context, caller) {
- const metadata = parseError(er, txt, context)
- super(metadata.message)
- Object.assign(this, metadata)
- this.code = 'EJSONPARSE'
- this.systemError = er
- Error.captureStackTrace(this, caller || this.constructor)
- }
- get name () {
- return this.constructor.name
- }
- set name (n) {}
- get [Symbol.toStringTag] () {
- return this.constructor.name
- }
- }
- const parseJson = (txt, reviver) => {
- const result = JSON.parse(txt, reviver)
- if (result && typeof result === 'object') {
- // get the indentation so that we can save it back nicely
- // if the file starts with {" then we have an indent of '', ie, none
- // otherwise, pick the indentation of the next line after the first \n If the
- // pattern doesn't match, then it means no indentation. JSON.stringify ignores
- // symbols, so this is reasonably safe. if the string is '{}' or '[]', then
- // use the default 2-space indent.
- const match = txt.match(EMPTY) || txt.match(FORMAT) || [null, '', '']
- result[NEWLINE] = match[1] ?? DEFAULT_NEWLINE
- result[INDENT] = match[2] ?? DEFAULT_INDENT
- }
- return result
- }
- const parseJsonError = (raw, reviver, context) => {
- const txt = stripBOM(raw)
- try {
- return parseJson(txt, reviver)
- } catch (e) {
- if (typeof raw !== 'string' && !Buffer.isBuffer(raw)) {
- const msg = Array.isArray(raw) && raw.length === 0 ? 'an empty array' : String(raw)
- throw Object.assign(
- new TypeError(`Cannot parse ${msg}`),
- { code: 'EJSONPARSE', systemError: e }
- )
- }
- throw new JSONParseError(e, txt, context, parseJsonError)
- }
- }
- module.exports = parseJsonError
- parseJsonError.JSONParseError = JSONParseError
- parseJsonError.noExceptions = (raw, reviver) => {
- try {
- return parseJson(stripBOM(raw), reviver)
- } catch {
- // no exceptions
- }
- }
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