diff --git a/README.md b/README.md index 7083b13b8..94145e6ee 100644 --- a/README.md +++ b/README.md @@ -246,6 +246,7 @@ average(1, 2, 3); * [`sleep`](#sleep) * [`throttle`](#throttle) * [`times`](#times) +* [`uncurry`](#uncurry) * [`unfold`](#unfold) @@ -4199,6 +4200,38 @@ console.log(output); // 01234
[⬆ Back to top](#table-of-contents) +### uncurry + +Uncurries a function up to depth `n`. + +Return a variadic function. +Use `Array.reduce()` on the provided arguments to call each subsequent curry level of the function. +If the `length` of the provided arguments is less than `n` throw an error. +Otherwise, call `fn` with the proper amount of arguments, using `Array.slice(0, n)`. +Omit the second argument, `n`, to uncurry up to depth `1`. + +```js +const uncurry = (fn, n = 1) => (...args) => { + const next = acc => args => args.reduce((x, y) => x(y), acc); + if (n > args.length) throw new RangeError('Arguments too few!'); + return next(fn)(args.slice(0, n)); +}; +``` + +
+Examples + +```js +const add = x => y => z => x + y + z; +const uncurriedAdd = uncurry(add, 3); +uncurriedAdd(1, 2, 3); // 6 +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + ### unfold Builds an array, using an iterator function and an initial seed value. diff --git a/docs/index.html b/docs/index.html index 385f479a6..6404e8899 100644 --- a/docs/index.html +++ b/docs/index.html @@ -50,7 +50,7 @@ scrollToTop(); } }, false); - }

logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.

 

Adapter

ary

Creates a function that accepts up to n arguments, ignoring any additional arguments.

Call the provided function, fn, with up to n arguments, using Array.slice(0,n) and the spread operator (...).

const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Adapter
ary
Creates a function that accepts up to n arguments, ignoring any additional arguments.
Call the provided function, fn, with up to n arguments, using Array.slice(0,n) and the spread operator (...).
const ary = (fn, n) => (...args) => fn(...args.slice(0, n));
 
const firstTwoMax = ary(Math.max, 2);
 [[2, 6, 'a'], [8, 4, 6], [10]].map(x => firstTwoMax(...x)); // [6, 8, 10]
 
call
Given a key and a set of arguments, call them when given a context. Primarily useful in composition.
Use a closure to call a stored key with stored arguments.
const call = (key, ...args) => context => context[key](...args);
@@ -967,6 +967,14 @@ document.bodyShow examples
var output = '';
 times(5, i => (output += i));
 console.log(output); // 01234
+
uncurry
Uncurries a function up to depth n.
Return a variadic function. Use Array.reduce() on the provided arguments to call each subsequent curry level of the function. If the length of the provided arguments is less than n throw an error. Otherwise, call fn with the proper amount of arguments, using Array.slice(0, n). Omit the second argument, n, to uncurry up to depth 1.
const uncurry = (fn, n = 1) => (...args) => {
+  const next = acc => args => args.reduce((x, y) => x(y), acc);
+  if (n > args.length) throw new RangeError('Arguments too few!');
+  return next(fn)(args.slice(0, n));
+};
+
const add = x => y => z => x + y + z;
+const uncurriedAdd = uncurry(add, 3);
+uncurriedAdd(1, 2, 3); // 6
 
unfold
Builds an array, using an iterator function and an initial seed value.
Use a while loop and Array.push() to call the function repeatedly until it returns false. The iterator function accepts one argument (seed) and must always return an array with two elements ([value, nextSeed]) or false to terminate.
const unfold = (fn, seed) => {
   let result = [],
     val = [null, seed];