Start up script for node.js repl

Question

Is there a way configure node.js\'s repl? I want to require jquery and underscore automatically whenever the repl starts. Is there a file (noderc?) that node.js loads when i

Answer 1

Might be a newer feature of Node.js (since this question is four years old), but you can load and save repl history like ipython.

.break - While inputting a multi-line expression, sometimes you get lost or just don't care about completing it. .break will start over.
.clear - Resets the context object to an empty object and clears any multi-line expression.
.exit - Close the I/O stream, which will cause the REPL to exit.
.help - Show this list of special commands.
.save - Save the current REPL session to a file
    .save ./file/to/save.js
.load - Load a file into the current REPL session.
    .load ./file/to/load.js

I can't figure out how to execute this automatically when starting the shell, but .load something is convenient enough for me at the moment.

Answer 2

I tried this today but .start required an argument. Also I think the useGlobal:true was important. I wound up using:

var myrepl=require('repl').start({useGlobal:true});
myrepl.context['myObj']=require('./myObject');

Saving this code in test.js I could do a node test.js then access myObj in REPL.

Answer 3

I don't know of any such configuration file, but if you want to have modules foo and bar be available in a REPL, you can create a file myrepl.js containing:

var myrepl = require("repl").start();
["foo", "bar"].forEach(function(modName){
    myrepl.context[modName] = require(modName); 
});

and you when you execute it with node myrepl.js you get a REPL with those modules available.

Armed with this knowledge you can put #!/path/to/node at the top and make it executable directly, or you could modify your version of the repl.js module (source available at https://github.com/joyent/node/blob/master/lib/repl.js for inspection) or whatever :)

Answer 4

Keeping things simple here's what I clabbered up.

repl.js:

// things i want in repl
global.reload = require('require-nocache')(module) // so I can reload modules as I edit them
global.r = require('ramda') // <3 http://ramdajs.com/
// launch, also capture ref to the repl, in case i want it later
global.repl = require('repl').start()

I can invoke this with node repl which feels right, and I don't care about globals, because I am just messin' around in the repl.

Answer 5

Feb 2017 - whilst I agree with the accepted answer, wished to add a little more commentary here.

Like to setup as follows (from home directory on my Mac)

.node ├── node_modules │   ├── lodash │   └── ramda ├── package.json └── repl.js

Then repl.js may look like as follows:

const repl = require('repl');

let r = repl.start({
  ignoreUndefined: true,
  replMode: repl.REPL_MODE_STRICT
});

r.context.lodash = require('lodash');
r.context.R = require('ramda');
// add your dependencies here as you wish..

And finally, put an alias into your .bashrc or .zshrc file etc (depending on your shell prefs) - something like:

alias noder='node ~/.node/repl.js'

Now, to use this configuration, you just have to type noder from the command line. Above, I also specified that I'd always like to be in strict mode, and do not want undefined printed to the console for declarations etc.

For up-to-date information on repl and in particular repl.start options see here