parse-json

Parse JSON with more helpful errors

Install

1npm install parse-json

Usage

1import parseJson, {JSONError} from 'parse-json';
2
3const json = '{\n\t"foo": true,\n}';
4
5
6JSON.parse(json);
7/*
8SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
9*/
10
11
12parseJson(json);
13/*
14JSONError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
15
16  1 | {
17  2 |   "foo": true,
18> 3 | }
19    | ^
20*/
21
22
23parseJson(json, 'foo.json');
24/*
25JSONError: Expected double-quoted property name in JSON at position 16 (line 3 column 1) in foo.json
26
27  1 | {
28  2 |   "foo": true,
29> 3 | }
30    | ^
31  fileName: 'foo.json',
32  [cause]: SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
33      at JSON.parse (<anonymous>)
34      at ...
35*/
36
37
38// You can also add the filename at a later point
39try {
40	parseJson(json);
41} catch (error) {
42	if (error instanceof JSONError) {
43		error.fileName = 'foo.json';
44	}
45
46	throw error;
47}
48/*
49JSONError: Expected double-quoted property name in JSON at position 16 (line 3 column 1) in foo.json
50
51  1 | {
52  2 |   "foo": true,
53> 3 | }
54    | ^
55
56  fileName: 'foo.json',
57  [cause]: SyntaxError: Expected double-quoted property name in JSON at position 16 (line 3 column 1)
58      at JSON.parse (<anonymous>)
59      at ...
60*/

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.