241 lines
8.1 KiB
JavaScript
241 lines
8.1 KiB
JavaScript
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const STR = 0b000000001;
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const NUM = 0b000000010;
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const ARR = 0b000000100;
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const OBJ = 0b000001000;
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const NULL = 0b000010000;
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const BOOL = 0b000100000;
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const NAN = 0b001000000;
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const INFINITY = 0b010000000;
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const MINUS_INFINITY = 0b100000000;
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const INF = INFINITY | MINUS_INFINITY;
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const SPECIAL = NULL | BOOL | INF | NAN;
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const ATOM = STR | NUM | SPECIAL;
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const COLLECTION = ARR | OBJ;
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const ALL = ATOM | COLLECTION;
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const Allow = {
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STR,
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NUM,
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ARR,
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OBJ,
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NULL,
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BOOL,
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NAN,
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INFINITY,
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MINUS_INFINITY,
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INF,
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SPECIAL,
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ATOM,
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COLLECTION,
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ALL,
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};
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// The JSON string segment was unable to be parsed completely
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class PartialJSON extends Error {
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}
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class MalformedJSON extends Error {
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}
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/**
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* Parse incomplete JSON
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* @param {string} jsonString Partial JSON to be parsed
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* @param {number} allowPartial Specify what types are allowed to be partial, see {@link Allow} for details
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* @returns The parsed JSON
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* @throws {PartialJSON} If the JSON is incomplete (related to the `allow` parameter)
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* @throws {MalformedJSON} If the JSON is malformed
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*/
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function parseJSON(jsonString, allowPartial = Allow.ALL) {
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if (typeof jsonString !== 'string') {
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throw new TypeError(`expecting str, got ${typeof jsonString}`);
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}
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if (!jsonString.trim()) {
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throw new Error(`${jsonString} is empty`);
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}
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return _parseJSON(jsonString.trim(), allowPartial);
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}
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const _parseJSON = (jsonString, allow) => {
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const length = jsonString.length;
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let index = 0;
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const markPartialJSON = (msg) => {
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throw new PartialJSON(`${msg} at position ${index}`);
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};
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const throwMalformedError = (msg) => {
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throw new MalformedJSON(`${msg} at position ${index}`);
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};
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const parseAny = () => {
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skipBlank();
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if (index >= length)
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markPartialJSON('Unexpected end of input');
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if (jsonString[index] === '"')
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return parseStr();
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if (jsonString[index] === '{')
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return parseObj();
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if (jsonString[index] === '[')
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return parseArr();
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if (jsonString.substring(index, index + 4) === 'null' ||
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(Allow.NULL & allow && length - index < 4 && 'null'.startsWith(jsonString.substring(index)))) {
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index += 4;
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return null;
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}
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if (jsonString.substring(index, index + 4) === 'true' ||
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(Allow.BOOL & allow && length - index < 4 && 'true'.startsWith(jsonString.substring(index)))) {
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index += 4;
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return true;
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}
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if (jsonString.substring(index, index + 5) === 'false' ||
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(Allow.BOOL & allow && length - index < 5 && 'false'.startsWith(jsonString.substring(index)))) {
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index += 5;
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return false;
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}
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if (jsonString.substring(index, index + 8) === 'Infinity' ||
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(Allow.INFINITY & allow && length - index < 8 && 'Infinity'.startsWith(jsonString.substring(index)))) {
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index += 8;
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return Infinity;
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}
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if (jsonString.substring(index, index + 9) === '-Infinity' ||
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(Allow.MINUS_INFINITY & allow &&
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1 < length - index &&
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length - index < 9 &&
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'-Infinity'.startsWith(jsonString.substring(index)))) {
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index += 9;
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return -Infinity;
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}
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if (jsonString.substring(index, index + 3) === 'NaN' ||
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(Allow.NAN & allow && length - index < 3 && 'NaN'.startsWith(jsonString.substring(index)))) {
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index += 3;
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return NaN;
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}
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return parseNum();
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};
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const parseStr = () => {
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const start = index;
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let escape = false;
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index++; // skip initial quote
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while (index < length && (jsonString[index] !== '"' || (escape && jsonString[index - 1] === '\\'))) {
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escape = jsonString[index] === '\\' ? !escape : false;
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index++;
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}
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if (jsonString.charAt(index) == '"') {
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try {
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return JSON.parse(jsonString.substring(start, ++index - Number(escape)));
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}
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catch (e) {
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throwMalformedError(String(e));
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}
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}
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else if (Allow.STR & allow) {
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try {
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return JSON.parse(jsonString.substring(start, index - Number(escape)) + '"');
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}
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catch (e) {
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// SyntaxError: Invalid escape sequence
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return JSON.parse(jsonString.substring(start, jsonString.lastIndexOf('\\')) + '"');
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}
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}
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markPartialJSON('Unterminated string literal');
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};
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const parseObj = () => {
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index++; // skip initial brace
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skipBlank();
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const obj = {};
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try {
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while (jsonString[index] !== '}') {
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skipBlank();
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if (index >= length && Allow.OBJ & allow)
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return obj;
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const key = parseStr();
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skipBlank();
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index++; // skip colon
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try {
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const value = parseAny();
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Object.defineProperty(obj, key, { value, writable: true, enumerable: true, configurable: true });
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}
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catch (e) {
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if (Allow.OBJ & allow)
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return obj;
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else
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throw e;
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}
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skipBlank();
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if (jsonString[index] === ',')
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index++; // skip comma
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}
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}
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catch (e) {
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if (Allow.OBJ & allow)
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return obj;
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else
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markPartialJSON("Expected '}' at end of object");
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}
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index++; // skip final brace
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return obj;
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};
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const parseArr = () => {
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index++; // skip initial bracket
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const arr = [];
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try {
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while (jsonString[index] !== ']') {
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arr.push(parseAny());
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skipBlank();
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if (jsonString[index] === ',') {
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index++; // skip comma
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}
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}
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}
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catch (e) {
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if (Allow.ARR & allow) {
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return arr;
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}
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markPartialJSON("Expected ']' at end of array");
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}
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index++; // skip final bracket
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return arr;
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};
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const parseNum = () => {
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if (index === 0) {
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if (jsonString === '-' && Allow.NUM & allow)
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markPartialJSON("Not sure what '-' is");
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try {
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return JSON.parse(jsonString);
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}
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catch (e) {
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if (Allow.NUM & allow) {
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try {
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if ('.' === jsonString[jsonString.length - 1])
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return JSON.parse(jsonString.substring(0, jsonString.lastIndexOf('.')));
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return JSON.parse(jsonString.substring(0, jsonString.lastIndexOf('e')));
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}
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catch (e) { }
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}
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throwMalformedError(String(e));
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}
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}
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const start = index;
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if (jsonString[index] === '-')
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index++;
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while (jsonString[index] && !',]}'.includes(jsonString[index]))
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index++;
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if (index == length && !(Allow.NUM & allow))
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markPartialJSON('Unterminated number literal');
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try {
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return JSON.parse(jsonString.substring(start, index));
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}
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catch (e) {
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if (jsonString.substring(start, index) === '-' && Allow.NUM & allow)
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markPartialJSON("Not sure what '-' is");
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try {
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return JSON.parse(jsonString.substring(start, jsonString.lastIndexOf('e')));
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}
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catch (e) {
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throwMalformedError(String(e));
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}
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}
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};
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const skipBlank = () => {
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while (index < length && ' \n\r\t'.includes(jsonString[index])) {
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index++;
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}
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};
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return parseAny();
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};
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// using this function with malformed JSON is undefined behavior
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const partialParse = (input) => parseJSON(input, Allow.ALL ^ Allow.NUM);
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export { partialParse, PartialJSON, MalformedJSON };
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//# sourceMappingURL=parser.mjs.map
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