JSON Stream Parser (TypeScript Edition)

This is a fully rewritten TypeScript version of the jsonparse library. Originally created by Tim Caswell in 2012, this version modernizes the approach by following OOP principles and introducing additional functionality.

Unlike the original, this version fully supports browser environments and provides enhanced features for better control over JSON parsing.

Features

• Streaming JSON parsing: Handles JSON data in chunks.
• Full browser support: Works both in Node.js and browser environments.
• Improved API: Additional methods for better parsing control.
• Event-driven architecture: Supports event emitters for handling tokens and values.
• Better error handling: Capture parsing errors more efficiently.

Installation

npm install @init-kz/jsonparse-ts

Usage

import { Parser } from '@init-kz/jsonparse-ts';

const parser = new Parser();
parser.write('[{"name": "A');
console.log(parser.getLastIncompleteValue()); // { name: "A" }

parser.write('"}, {"na');
console.log(parser.getLastIncompleteValue()); // { name: "A" }, { }

parser.write('me": "Occaecat aliq');
console.log(parser.getLastIncompleteValue()); // { name: "A" }, { name: "Occaecat aliq" }

parser.write('uip id officia ipsum deserunt ea id labore magna qui elit dolore consectetur dolore.');
console.log(parser.getLastValue()); // Full JSON structure

API

getEmitter(): EventEmitter

Returns the event emitter used internally by the parser.

onToken(callback: (token: number, value: any) => void): void

Registers a callback for when a token is parsed.

onValue(callback: (value: any) => void): void

Registers a callback for when a complete value is parsed.

onError(callback: (err: Error) => void): void

Registers a callback for handling errors.

getLastValue(): any

Retrieves the last fully parsed value.

getLastIncompleteValue(omitEmpty?: boolean): any

Retrieves the last partially parsed value, except numbers.

getCurrentKey(): string | number | undefined

Gets the current key being parsed in an object.

getStack(): { value: any; key?: string | number; mode?: number; }[]

Returns the internal parsing stack.

getOffset(): number

Returns the current byte offset in the stream.

write(chunk: string | Uint8Array): void

Processes a chunk of JSON data.

Contributing

Contributions are welcome! Feel free to submit issues or open pull requests to improve the project.

License

The MIT License

Copyright (c) 2012 Tim Caswell
Copyright (c) 2025 INIT.KZ