diff --git a/README.md b/README.md index 8baa1bfdc..ec2ea9f30 100644 --- a/README.md +++ b/README.md @@ -229,6 +229,8 @@ average(1, 2, 3); * [`memoize`](#memoize) * [`negate`](#negate) * [`once`](#once) +* [`partial`](#partial) +* [`partialRight`](#partialright) * [`runPromisesInSeries`](#runpromisesinseries) * [`sleep`](#sleep) * [`times`](#times) @@ -3502,6 +3504,58 @@ document.body.addEventListener('click', once(startApp)); // only runs `startApp`
[⬆ Back to top](#table-of-contents) +### partial + +Creates a function that invokes `fn` with `partials` prepended to the arguments it receives. + +Use the spread operator (`...`) to prepend `partials` to the list of arguments of `fn`. + +```js +const partial = (fn, ...partials) => (...args) => fn(...partials, ...args); +``` + +
+Examples + +```js +function greet(greeting, name) { + return greeting + ' ' + name + '!'; +} +const greetHello = partial(greet, 'Hello'); +greetHello('John'); // 'Hello John!' +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + +### partialRight + +Creates a function that invokes `fn` with `partials` appended to the arguments it receives. + +Use the spread operator (`...`) to append `partials` to the list of arguments of `fn`. + +```js +const partialRight = (fn, ...partials) => (...args) => fn(...args, ...partials); +``` + +
+Examples + +```js +function greet(greeting, name) { + return greeting + ' ' + name + '!'; +} +const greetJohn = partialRight(greet, 'John'); +greetJohn('Hello'); // 'Hello John!' +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + ### runPromisesInSeries Runs an array of promises in series. diff --git a/docs/index.html b/docs/index.html index 609f08592..1a7e18bfc 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);
@@ -786,6 +786,18 @@ console.log<
   console.log(this, event); // document.body, MouseEvent
 };
 document.body.addEventListener('click', once(startApp)); // only runs `startApp` once upon click
+
partial
Creates a function that invokes fn with partials prepended to the arguments it receives.
Use the spread operator (...) to prepend partials to the list of arguments of fn.
const partial = (fn, ...partials) => (...args) => fn(...partials, ...args);
+
function greet(greeting, name) {
+  return greeting + ' ' + name + '!';
+}
+const greetHello = partial(greet, 'Hello');
+greetHello('John'); // 'Hello John!'
+
partialRight
Creates a function that invokes fn with partials appended to the arguments it receives.
Use the spread operator (...) to append partials to the list of arguments of fn.
const partialRight = (fn, ...partials) => (...args) => fn(...args, ...partials);
+
function greet(greeting, name) {
+  return greeting + ' ' + name + '!';
+}
+const greetJohn = partialRight(greet, 'John');
+greetJohn('Hello'); // 'Hello John!'
 
runPromisesInSeries
Runs an array of promises in series.
Use Array.reduce() to create a promise chain, where each promise returns the next promise when resolved.
const runPromisesInSeries = ps => ps.reduce((p, next) => p.then(next), Promise.resolve());
 
const delay = d => new Promise(r => setTimeout(r, d));
 runPromisesInSeries([() => delay(1000), () => delay(2000)]); // Executes each promise sequentially, taking a total of 3 seconds to complete
diff --git a/snippets/partialRight.md b/snippets/partialRight.md
index 6b6aa1131..d64f7f1d6 100644
--- a/snippets/partialRight.md
+++ b/snippets/partialRight.md
@@ -5,7 +5,7 @@ Creates a function that invokes `fn` with `partials` appended to the arguments i
 Use the spread operator (`...`) to append `partials` to the list of arguments of `fn`.
 
 ```js
-const partialRight = (fn, ...partials) => (...args) => fn( ...args, ...partials);
+const partialRight = (fn, ...partials) => (...args) => fn(...args, ...partials);
 ```
 
 ```js