codekingpro/portable-devtools

1'use strict'
2
3const INDENT = Symbol.for('indent')
4const NEWLINE = Symbol.for('newline')
5
6const DEFAULT_NEWLINE = '\n'
7const DEFAULT_INDENT = '  '
8const BOM = /^\uFEFF/
9
10// only respect indentation if we got a line break, otherwise squash it
11// things other than objects and arrays aren't indented, so ignore those
12// Important: in both of these regexps, the $1 capture group is the newline
13// or undefined, and the $2 capture group is the indent, or undefined.
14const FORMAT = /^\s*[{[]((?:\r?\n)+)([\s\t]*)/
15const EMPTY = /^(?:\{\}|\[\])((?:\r?\n)+)?$/
16
17// Node 20 puts single quotes around the token and a comma after it
18const UNEXPECTED_TOKEN = /^Unexpected token '?(.)'?(,)? /i
19
20const hexify = (char) => {
21  const h = char.charCodeAt(0).toString(16).toUpperCase()
22  return `0x${h.length % 2 ? '0' : ''}${h}`
23}
24
25// Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
26// because the buffer-to-string conversion in `fs.readFileSync()`
27// translates it to FEFF, the UTF-16 BOM.
28const stripBOM = (txt) => String(txt).replace(BOM, '')
29
30const makeParsedError = (msg, parsing, position = 0) => ({
31  message: `${msg} while parsing ${parsing}`,
32  position,
33})
34
35const parseError = (e, txt, context = 20) => {
36  let msg = e.message
37
38  if (!txt) {
39    return makeParsedError(msg, 'empty string')
40  }
41
42  const badTokenMatch = msg.match(UNEXPECTED_TOKEN)
43  const badIndexMatch = msg.match(/ position\s+(\d+)/i)
44
45  if (badTokenMatch) {
46    msg = msg.replace(
47      UNEXPECTED_TOKEN,
48      `Unexpected token ${JSON.stringify(badTokenMatch[1])} (${hexify(badTokenMatch[1])})$2 `
49    )
50  }
51
52  let errIdx
53  if (badIndexMatch) {
54    errIdx = +badIndexMatch[1]
55  } else /* istanbul ignore next - doesnt happen in Node 22 */ if (
56    msg.match(/^Unexpected end of JSON.*/i)
57  ) {
58    errIdx = txt.length - 1
59  }
60
61  if (errIdx == null) {
62    return makeParsedError(msg, `'${txt.slice(0, context * 2)}'`)
63  }
64
65  const start = errIdx <= context ? 0 : errIdx - context
66  const end = errIdx + context >= txt.length ? txt.length : errIdx + context
67  const slice = `${start ? '...' : ''}${txt.slice(start, end)}${end === txt.length ? '' : '...'}`
68
69  return makeParsedError(
70    msg,
71    `${txt === slice ? '' : 'near '}${JSON.stringify(slice)}`,
72    errIdx
73  )
74}
75
76class JSONParseError extends SyntaxError {
77  constructor (er, txt, context, caller) {
78    const metadata = parseError(er, txt, context)
79    super(metadata.message)
80    Object.assign(this, metadata)
81    this.code = 'EJSONPARSE'
82    this.systemError = er
83    Error.captureStackTrace(this, caller || this.constructor)
84  }
85
86  get name () {
87    return this.constructor.name
88  }
89
90  set name (n) {}
91
92  get [Symbol.toStringTag] () {
93    return this.constructor.name
94  }
95}
96
97const parseJson = (txt, reviver) => {
98  const result = JSON.parse(txt, reviver)
99  if (result && typeof result === 'object') {
100    // get the indentation so that we can save it back nicely
101    // if the file starts with {" then we have an indent of '', ie, none
102    // otherwise, pick the indentation of the next line after the first \n If the
103    // pattern doesn't match, then it means no indentation. JSON.stringify ignores
104    // symbols, so this is reasonably safe. if the string is '{}' or '[]', then
105    // use the default 2-space indent.
106    const match = txt.match(EMPTY) || txt.match(FORMAT) || [null, '', '']
107    result[NEWLINE] = match[1] ?? DEFAULT_NEWLINE
108    result[INDENT] = match[2] ?? DEFAULT_INDENT
109  }
110  return result
111}
112
113const parseJsonError = (raw, reviver, context) => {
114  const txt = stripBOM(raw)
115  try {
116    return parseJson(txt, reviver)
117  } catch (e) {
118    if (typeof raw !== 'string' && !Buffer.isBuffer(raw)) {
119      const msg = Array.isArray(raw) && raw.length === 0 ? 'an empty array' : String(raw)
120      throw Object.assign(
121        new TypeError(`Cannot parse ${msg}`),
122        { code: 'EJSONPARSE', systemError: e }
123      )
124    }
125    throw new JSONParseError(e, txt, context, parseJsonError)
126  }
127}
128
129module.exports = parseJsonError
130parseJsonError.JSONParseError = JSONParseError
131parseJsonError.noExceptions = (raw, reviver) => {
132  try {
133    return parseJson(stripBOM(raw), reviver)
134  } catch {
135    // no exceptions
136  }
137}
138