Added compose such that the rightmost function may have any arity. Added spread operator to explanation of pipe.

This commit is contained in:
Justin Lee
2017-12-15 07:39:39 -08:00
parent 7d874b0862
commit 3c48c3b5d8
2 changed files with 15 additions and 1 deletions

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### Compose
Use `Array.reduce()` with the spread operator (`...`) to perform right-to-;eft function composition.
The last (rightmost) function can accept one or more arguments; the remaining functions must be unary.
```js
const compose = (...fns) => fns.reduce((f, g) => (...args) => f(g(...args)));
/*
const add5 = x => x + 5
const multiply = (x, y) => x * y
const multiplyAndAdd5 = compose(add5, multiply)
multiplyAndAdd5(5, 2) -> 15
*/
```

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### Pipe ### Pipe
Use `Array.reduce()` to perform left-to-right function composition. Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition.
The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. The first (leftmost) function can accept one or more arguments; the remaining functions must be unary.
```js ```js