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