parse-json

Parse JSON with more helpful errors

Install

npm install parse-json

Usage

import parseJson, {JSONError} from 'parse-json';

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


JSON.parse(json);
/*
SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
*/


parseJson(json);
/*
JSONError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)

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


parseJson(json, 'foo.json');
/*
JSONError: Expected double-quoted property name in JSON at position 16 (line 3 column 1) in foo.json

  1 | {
  2 |   "foo": true,
> 3 | }
    | ^
  fileName: 'foo.json',
  [cause]: SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
      at JSON.parse (<anonymous>)
      at ...
*/


// 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: Expected double-quoted property name in JSON at position 16 (line 3 column 1) in foo.json

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

  fileName: 'foo.json',
  [cause]: SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
      at JSON.parse (<anonymous>)
      at ...
*/

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.

rawCodeFrame

Type: string

The raw version of codeFrame without colors.