A Document Path Library for Node

This module will take paths in documents which can include nested paths specified by '.'s and can evaluate the path to a value, or can set the value at that path depending on the function called.

Installation

1$ npm install doc-path

Usage

1let path = require('doc-path');

API

path.evaluatePath(document, key)

• document - Object - A JSON document that will be iterated over.
• key - String - A path to the existing key whose value will be returned.
  • Note: If your key has a dot in it (eg. a.b) then be sure to escape the dot with a blackslash (eg. a\\.b).

If the key does not exist, undefined is returned.

If the object's structure is extremely deep, then an error may be thrown if the maximum call stack size is exceeded while traversing the object.

path.evaluatePath Example:

1const path = require('doc-path');
2
3let document = {
4    Make: 'Nissan',
5    Model: 'Murano',
6    Year: '2013',
7    Specifications: {
8        Mileage: '7106',
9        Trim: 'S AWD'
10    },
11    Features: [
12		{
13		    feature: 'A/C',
14			packages: [
15				{name: 'Base'},
16				{name: 'Premium'}
17			]
18		},
19		{
20		    feature: 'Radio',
21			packages: [
22				{name: 'Convenience'},
23				{name: 'Premium'}
24			]
25		}
26	]
27};
28
29console.log(path.evaluatePath(document, 'Make'));
30// => 'Nissan'
31
32console.log(path.evaluatePath(document, 'Specifications.Mileage'));
33// => '7106'
34
35console.log(path.evaluatePath(document, 'Features.feature'));
36// => [ 'A/C', 'Radio' ]
37
38console.log(path.evaluatePath(document, 'Features.packages.name'));
39// => [ ['Base', 'Premium'], ['Convenience', 'Premium'] ]

path.setPath(document, key, value)

• document - Object - A JSON document that will be iterated over.
• key - String - A path to the existing key whose value will be set.
  • Note: If your key has a dot in it (eg. a.b) then be sure to escape the dot with a blackslash (eg. a\\.b).
• value - * - The value that will be set at the given key.

If the key does not exist, then the object will be built up to have that path. If no document is provided, an error will be thrown. If the object's structure is extremely deep, then an error may be thrown if the maximum call stack size is exceeded while traversing the object.

path.setPath Example:

1const path = require('doc-path');
2
3let document = {
4    Make: 'Nissan',
5    Features: [
6        { feature: 'A/C' }
7    ]
8};
9
10console.log(path.setPath(document, 'Color.Interior', 'Tan'));
11/*
12   { 
13   	Make: 'Nissan',
14   	Features: [
15   		{ feature: 'A/C' }
16   	]
17   	Color: { 
18   		Interior: 'Tan'
19   	}
20   }
21*/
22
23console.log(path.setPath(document, 'StockNumber', '34567'));
24/*
25   { 
26   	Make: 'Nissan',
27   	Features: [
28   		{ feature: 'A/C' }
29   	]
30   	Color: { 
31   		Interior: 'Tan'
32   	},
33   	StockNumber: '34567'
34   }
35*/
36
37console.log(path.setPath(document, 'Features.cost', '$0 (Standard)'));
38 /*
39	{ 
40   	Make: 'Nissan',
41   	Features: [
42   		{
43   			feature: 'A/C',
44   			cost: '$0 (Standard)'
45   		}
46   	]
47   	Color: { 
48   		Interior: 'Tan'
49   	},
50   	StockNumber: '34567'
51	}
52 */

Tests

1$ npm test

Note: This requires mocha, should, async, and underscore.

To see test coverage, please run:

1$ npm run coverage

Current Coverage is:

Statements   : 100% ( 33/33 )
Branches     : 100% ( 24/24 )
Functions    : 100% ( 3/3 )
Lines        : 100% ( 29/29 )

Features

• Supports keys with escaped . characters (as of v3.0.0)
• Supports nested paths
  • Including keys of objects inside arrays! (as of v2.0.0)
• Same common path specification as other programs such as MongoDB