Node.js - passing variable to multiple functions within async.parallel

Question

Node.js - passing variable to multiple functions within async.parallel

I have a set of functions that get dynamically loaded. Each function is in its own file and looks like:

module.exports = function(incomingData, done) {
    var test = incomingData + " foo -->"
    done(null, test);
};

These are loaded in to an object ('allPluggins') that then looks like:

{ 'test-bar': [Function], 'test-foo': [Function] }

I wish to execute all functions using async.parallel passing the same 'incomingData' variable to each.

So far I have:

async.parallel(allPluggins, done());

Can anyone advise how I can call async.parallel passing in the same 'incomingData' variable to each function?

javascript
node.js
function
asynchronous

Answer 1

You could wrap each function or bind() each one. Examples:

Using wrapper functions:

var incomingData = 'hello world';

Object.keys(allPluggins).forEach(function(key) {
  var fn = allPluggins[key];
  allPluggins[key] = function(done) {
    fn(incomingData, done);
  };
});

async.parallel(allPluggins, done);

Using bind():

var incomingData = 'hello world';

var key;
for (key in allPluggins)
  allPluggins[key] = allPluggins[key].bind(undefined, incomingData);

async.parallel(allPluggins, done);