json-locator

json-locator

Because all the good names (json-query, json-select, etc) were all taken up, I'm forced to use this name.

Essentially a thin wrapper around the excellent jsonpath library. The JSONPath specification is sketchy (I mean look at that website, 2007?) and not many people use it, but I needed something that would refer to specific nodes or groups of nodes.

Usage

var locator = require('json-locator');
var data = {
    colors: [
        { type: 'additive', name: 'red', red: 255, green: 0, blue: 0 },
        { type: 'additive', name: 'green', red: 0, green: 255, blue: 0 },
        { type: 'additive', name: 'blue', red: 0, green: 0, blue: 255 },
        { type: 'subtractive', name: 'cyan', red: 0, green: 255, blue: 255 },
        { type: 'subtractive', name: 'magenta', red: 255, green: 0, blue: 255 },
        { type: 'subtractive', name: 'yellow', red: 255, green: 255, blue: 0 },
        { type: 'subtractive', name: 'black', red: 0, green: 0, blue: 0 }
    ]
};

locator.transform('colors[type="subtractive"][red<100]'); 
// expected colors[?(@.type=="subtractive" && @.red<100)]

locator.query(data, 'colors[type="subtractive"][red<100]');
// expected [ { ... name: 'cyan' ...}, { ... name: 'black' ...} ]

Motivation

The npm module jsonpath has an excellent implementation and looks well maintained but:

• It evaluates filter expressions using esprima, which means using == instead of = and boolean operators like &&.
• It uses the annoying @ syntax which is unnecessary 99% of the time.

I wanted to filter something like:

"inputs": [     
    {
        "type": "dropdown",
        "data": {
            "name": "Memory",
            "hasPricing": true,
            "hasFrequency": false,
            "options": [
                {
                    "name": "one",
                    "price": "23",
                    "frequency": ""
                },
                {
                    "name": "two",
                    "price": "99",
                    "frequency": ""
                }
            ]
        }
    }
]

with an expression such as

inputs[type="dropdown"][data.hasPricing].data.options[*].price

and get back

["23", "99"]

and not have to use an expression like

inputs[?(@.type=="dropdown" && @.data.hasPricing)].data.options[*].price