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dot-compose

Combines the tersness of chaining with the power and flexibility of function composition. It temporarily redefines JavaScripts property access operator . into meaning function composition.

Example

With Ramda.

var r = dotCompose.Group(R); // Creates a compose group with all functions in `R`

//    ╭── Starts composition
//    │
//    │       ╭──────┬────────── The dots represents composition
//    ↓       ↓      ↓
R.map(r.add(2).negate.divide(R.__, 3).$, [3, 6, 9, 12]); //=> [1, 0, -1, -2]
//          ↑                ↑        ↑
//          │                │        ╰── The dollar sign ends the composition
//          │                │
//          ╰── Partial application works with curried functions

Tutorial

Composition groups

A composition group is created with Group.

var c = dotCompose.Group();

Supplying an object adds all functions in the object to the group.

var r = dotCompose.Group({
  half: function(n) { return n / 2; },
  square: function(n) { return n * n; },
});

Functions can be added to a group with add.

var group = dotCompose.Group();
dotCompose.add(group, function add(n, m) { return n + m; });

add returns the added function unchanged.

var group = dotCompose.Group();
var add = dotCompose.add(group, function add(n, m) { return n + m; });

Function injection

Only functions in the same composition group can be composed together. Arbitrary functions can be injected and composed with functions from a group by using _.

var add3 = function(n) { return n + 3; };
var c = dotCompose.Group({
  half: function(n) { return n / 2; },
  square: function(n) { return n * n; },
});
c.half._(add3).square(5); //=> 14

Currying of composed functions

If you supply dot-compose a curry function it will automatically curry the composed functions.

dotCompose.curryN(R.curryN);

Environment support

dot-compose uses getters from ECMAScript 4. It works from Internet Explore 9 and in everything else.