allow keys to be json paths about json-2-csv

[mrodrig]

Hi @jimthedev, thanks!

I can definitely see the usefulness of supporting keys nested in arrays, which it appears the current keys option doesn't support based on my testing. Unfortunately I won't have time to look into this for a little bit (because of grad school exams coming up), but it would be a nice addition.

Just for future reference, here's what I tried with the current code:

var converter = require('json-2-csv');

var options = {
    keys : ['Make', 'Model', 'Year', 'Features.name']
};

var documents = [
    {
        Make: 'Nissan',
        Model: ' Murano ', // Note: This value has additional padding which can be trimmed
        Year: '2013',
        Features: [{ name: 'AC', value: 1}, {name: 'DVD', value: 2}]
    }
];

var json2csvCallback = function (err, csv) {
    if (err) throw err;
    console.log(csv);
};

converter.json2csv(documents, json2csvCallback, options);

[jimthedev]

Cool. That looks similar to what I have been testing (which currently doesn't work). If I get to it I'll do a PR. Thanks for confirming.

[mrodrig]

As of 3.2.0, this is now supported! So for the following JSON documents, you can specify {keys: ['features.name']} in your options and it will pull the correct values:

[
        {
            "name": "list",
            "features": [
                {
                    "name": "modules"
                },
                {
                    "pros": "efficiency"
                },
                {
                    "cons": ["cost", "time"]
                }
            ]
        },
        {
            "name": "module",
            "features": [
                {
                    "name": "testing"
                }
            ],
            "downloads": "5k/m"
        }
    ]

However, if you want to take full advantage of the latest changes and have the most user-friendly CSV, then I'd also recommend specifying expandArrayObjects: true in your options object. That will tell the module that it should also parse array objects so that they're a bit more readable. The generated CSV when using this option will look like this for the above pasted JSON:

features.name
modules
testing

Thanks for reporting this and for your patience!