REST client in node.js

Question

I'm fairly new to node.js and I'm trying to make a simple node.js REST client to act as an SDK between an API and a larger application.

This is the current code in the client SDK part corresponding to index.js:

var unirest = require('unirest');
var config = require('config');

var host = config.get('api.host');

unirest.get(host + '/api/products?_format=json')
    .headers({'Accept': 'application/json', 'Content-Type': 'application/json'})
    .end(function (response) {
            console.log(response.body);
            module.exports.getProducts = function() {
                return response.body;
            }
    });

If I execute in the terminal: node index.js the console.log command returns the expected result from the API call

However if I install the package in the main project (as a local dependency) it does not seem to work.

Here is the code from the index.js in the main project:

var SDK = require('api-sdk-js');

var result = SDK.getProducts;
console.log(result);

In this case when I execute node index.js the console.log command returns undefined for the result variable, I suspect this is due to the GET call in the SDK being asynchronous so it returns the value before there is a response.

I'm not sure how to fix this, any suggestions?

Alternatively it would also work for me a good example of a REST API client in node.js as an SDK (i.e., as a package able to be installed from another project).

Answer 1

Your unirest call should really be inside your module.exports.getProducts method.

Due to the call being asynchronous, you can't just return from it. You need some sort of callback.

module.exports.getProducts = function(callback) {
    unirest.get(host + '/api/products?_format=json')
        .headers({'Accept': 'application/json', 'Content-Type': 'application/json'})
        .end(function (response) {
            callback(response.body);
        }); 
};

You'd then use it like so:

var SDK = require('./api-sdk-js');
SDK.getProducts(function(products) {
     console.log(products); // Should contain data from the callback
});

Read How do I return the response from an asynchronous call? for other alternatives to asynchronous JavaScript.