Set a Javascript function to be all the code in another .js file

Question

I have a file doSomething.js that contains some code that needs to be run both from the command line (eg: node doSomething.js) and also from a nodejs-based queue worker

queueWorker.js

var worker = client.worker(['example']);

worker.register({
    doSomething: function (params, callback) {
        // run the code contained in doSomething.js
    }
});

worker.start();

doSomething.js

console.log('Hello world')

Question: Is there a way to let the main code remain in doSomething.js and just include a reference to doSomething.js in queueWorker.js? I dont want to have 2 copies of the same code in 2 different files.

If the both files are referred on a HTML page with a proper sequence then this can be achieved. — Amogh
– Amogh, Commented Jul 23, 2015 at 19:13

otupman · Accepted Answer · 2015-07-23 19:29:40Z

So if I understand you correctly you've some code in a project that you want to be used by a command-line node script and by a worker. You don't mention how you deploy this code, so I'm going to assume that the stuff running the worker is the same codebase as the command line.

In which case I would assume that one solution is to make your doSomething.js use the standard NodeJS module system, i.e. something like

doSomething.js

module.exports = function() {
  console.log('Hello, world');
}

queueWorker.js

Your worker would become something like:

var worker = client.worker(['example']);
var doSomething = require('path/to/doSomething');
worker.register({
    doSomething: function (params, callback) {
        doSomething();
    }
});

worker.start();

doSomethingCli.js

Your command line script would be a totally separate script to the above (assuming that's okay), looking something similar to the worker:

var doSomething = require('path/to/doSomething');
doSomething();

While you stated you wanted to have doSomething.js callable from the command line that isn't a great solution - you'll find yourself starting to put cli stuff into doSomething.js which will break your queue worker. Keep the common code separate.

Yevgen Safronov · Accepted Answer · 2015-07-23 19:21:55Z

1

I assume you are using node for both cases.

queueWorker.js

var doSomething = require('./doSomething');
var worker = client.worker(['example']);

worker.register({
    doSomething: function (params, callback) {
       doSomething(params, callback);
    }
});

worker.start();

doSomething.js

module.exports = functionv(params, callback) {
 console.log('Hello world');
}

answered Jul 23, 2015 at 19:21

Yevgen Safronov

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Comments

6502 · Accepted Answer · 2015-07-23 19:20:57Z

0

Javascript is a dynamic language and it's always possible to eval a string containing code. For example you can do this

// file1.js -------------------------

function foo() {
    console.log("Hello, world.");
}

// file2.js -------------------------

eval(require('fs').readFileSync("file1.js", "utf-8"));
foo();

Of course node.js contains a much better approach if the code is indeed static and you just want to share it between different projects (the idea of modules).

answered Jul 23, 2015 at 19:20

6502

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