@esmkit/parse-json

Parse JSON with more helpful errors

Install

npm install @esmkit/parse-json

Usage

import parseJson, { JSONError } from "@esmkit/parse-json";

const json = '{\n\t"foo": true,\n}';

JSON.parse(json);
/*
undefined:3
}
^
SyntaxError: Unexpected token }
*/

parseJson(json);
/*
JSONError: Unexpected token } in JSON at position 16 while parsing near '{      "foo": true,}'

  1 | {
  2 |   "foo": true,
> 3 | }
    | ^
*/

parseJson(json, "foo.json");
/*
JSONError: Unexpected token } in JSON at position 16 while parsing near '{      "foo": true,}' in foo.json

  1 | {
  2 |   "foo": true,
> 3 | }
    | ^
*/

// You can also add the filename at a later point
try {
  parseJson(json);
} catch (error) {
  if (error instanceof JSONError) {
    error.fileName = "foo.json";
  }

  throw error;
}
/*
JSONError: Unexpected token } in JSON at position 16 while parsing near '{      "foo": true,}' in foo.json

  1 | {
  2 |   "foo": true,
> 3 | }
    | ^
*/

API

parseJson(string, reviver?, filename?)

Throws a JSONError when there is a parsing error.

string

Type: string

reviver

Type: Function

Prescribes how the value originally produced by parsing is transformed, before being returned. See JSON.parse docs for more.

filename

Type: string

The filename displayed in the error message.

JSONError

Exposed for instanceof checking.

fileName

Type: string

The filename displayed in the error message.

codeFrame

Type: string

The printable section of the JSON which produces the error.