https://github.com/paldepind/dot-compose

Function composition with dot as a composition operator.
https://github.com/paldepind/dot-compose

Last synced: 15 days ago
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Function composition with dot as a composition operator.

• Host: GitHub
• URL: https://github.com/paldepind/dot-compose
• Owner: paldepind
• License: mit
• Created: 2015-06-06T13:10:29.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2015-06-24T18:07:55.000Z (over 9 years ago)
• Last Synced: 2024-04-17T02:59:33.107Z (7 months ago)
• Language: JavaScript
• Homepage:
• Size: 145 KB
• Stars: 23
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# 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.

```javascript

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`.

```javascript

var c = dotCompose.Group();

```

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

```javascript

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`.

```javascript

var group = dotCompose.Group();

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

```

`add` returns the added function unchanged.

```javascript

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 `_`.

```javascript

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.

```javascript

dotCompose.curryN(R.curryN);

```

## Environment support

dot-compose uses getters from ECMAScript 4. It works from Internet Explore 9

and in everything else.