Pass JSON as command line argument to Node

Question

I'd like to pass a JSON object as a command line argument to node. Something like this:

node file.js --data { "name": "Dave" }

What's the best way to do this or is there another more advisable way to do accomplish the same thing?

Answer 1

this works for me:

$ node foo.js --json-array='["zoom"]'

then in my code I have:

  import * as _ from 'lodash';

  const parsed = JSON.parse(cliOpts.json_array || []);

  _.flattenDeep([parsed]).forEach(item => console.log(item));

I use dashdash, which I think is the best choice when it comes to command line parsing.

To do the same thing with an object, just use:

$ node foo.js --json-object='{"bar": true}'

Answer 2

if its a small amount of data, I'd use https://www.npmjs.com/package/minimist, which is a command line argument parser for nodejs. It's not json, but you can simply pass options like

--name=Foo 

or

-n Foo

I think this is better suited for a command line tool than json.

If you have a large amount of data you want to use you're better of with creating a json file and only pass the file name as command line argument, so that your program can load and parse it then.

Big objects as command line argument, most likely, aren't a good idea.