What is the syntax to pass a function and it arguments to another function to execute it?

Question

I have a foo function:

var foo = function(input) {
  console.log(input)
}

And a bar function:

var bar = function(fn, condition) {
  if (condition) {
    fn();
  }
}

I would like to pass foo as an argument of bar like: bar(foo, true);

The problem is that foo must be called executing a parameter. If I use bar(foo('param'), false);, foo will be executed before bar starts and check the condition.

Is there a better solution in JavaScript syntax?

I know that I could modify my bar function to the following, but I don't want to modify the bar implementation:

var bar = function(fn, fnParam, condition) {
  if (condition) {
    fn(fnParam);
  }
}

Siderite Zackwehdex · Accepted Answer · 2016-04-09T16:19:39.387

2

You can use this format: bar(function() { foo(param); },false), unless you need the meta information in the foo function, like name, in which case you need to use the function(fn, paramArray, condition)... method

Note that with new Javascript features, such as Arrow functions, you can write the same thing with bar(()=>foo(param),false), but not all browsers support this syntax.

edited Apr 09 '16 at 16:19

answered Apr 09 '16 at 16:07

Siderite Zackwehdex

6,293
3
30
46

Great! That's not so readable as I would expect, but is good enough! – kimb Apr 09 '16 at 16:11
1

`->` is not an arrow function, `=>` is. – Sebastian Simon Apr 09 '16 at 16:14
You're right. Fixed the typo. – Siderite Zackwehdex Apr 09 '16 at 16:19
1

@kimb: If your function doesn't need the `this` value to be set by the caller, you can do `bar(foo.bind(null, param), false)` – Apr 09 '16 at 16:28

What is the syntax to pass a function and it arguments to another function to execute it?

1 Answers1