/ts-json-parser

Primary LanguageTypeScript

ts-json-parser

A JSON parser in TypeScript made from scratch without JSON.parse or eval.

Usage

parser.ts exports the parse function as its default export.

Example

import parse from "./parser.ts"

const result = parse(`{
  "hello": "world",
  "foo": "bar"
}`)

console.log(result) // { "hello": "world", "foo": "bar" }

parse(`{ "hello": "world", "foo": }`) // Error: Expected value at index 27

Testing

This parser passes 100% of the tests in JSON Parsing Test Suite.

To run tests locally, install Deno. Make a folder called tests in this projects root directory. Copy the tests from test_parsing into tests. Run deno run test.ts.

This checks that:

  1. the parser errors on invalid json
  2. the parser succeeds on valid json
  3. on valid json, the resulting value matches JSON.parse

Why

JSON.parse already exists, so I really just did this for fun! The awesome railroad diagrams on json.org made it really appealing.