Performs left-to-right function composition for asynchronous functions.
Use Array.prototype.reduce() with the spread operator (...) to perform left-to-right function composition using Promise.then(). The functions can return a combination of: simple values, Promise's, or they can be defined as async ones returning through await. All functions must be unary.
const pipeAsyncFunctions = (...fns) => arg => fns.reduce((p, f) => p.then(f), Promise.resolve(arg)); -
-const sum = pipeAsyncFunctions( +
const sum = pipeAsyncFunctions( x => x + 1, x => new Promise(resolve => setTimeout(() => resolve(x + 2), 1000)), x => x + 3, diff --git a/docs/index.html b/docs/index.html index 05c919edc..31c814551 100644 --- a/docs/index.html +++ b/docs/index.html @@ -403,8 +403,7 @@
Takes a predicate and array, like Array.prototype.filter(), but only keeps x if pred(x) === false.
const reject = (pred, array) => array.filter((...args) => !pred(...args));
reject(x => x % 2 === 0, [1, 2, 3, 4, 5]); // [1, 3, 5] reject(word => word.length > 4, ['Apple', 'Pear', 'Kiwi', 'Banana']); // ['Pear', 'Kiwi'] -
Removes elements from an array for which the given function returns false.
Use Array.prototype.filter() to find array elements that return truthy values and Array.prototype.reduce() to remove elements using Array.prototype.splice(). The func is invoked with three arguments (value, index, array).
-const remove = (arr, func) => +
Removes elements from an array for which the given function returns false.
Use Array.prototype.filter() to find array elements that return truthy values and Array.prototype.reduce() to remove elements using Array.prototype.splice(). The func is invoked with three arguments (value, index, array).
const remove = (arr, func) => Array.isArray(arr) ? arr.filter(func).reduce((acc, val) => { arr.splice(arr.indexOf(val), 1); diff --git a/docs/math.html b/docs/math.html index 7d25685e1..03bc22d01 100644 --- a/docs/math.html +++ b/docs/math.html @@ -147,8 +147,7 @@ For teams, each rating can adjusted based on own team's average rating vs. average rating of opposing team, with the score being added to their own individual rating by supplying it as the third argument. */ -
Calculates the factorial of a number.
Use recursion. If n is less than or equal to 1, return 1. Otherwise, return the product of n and the factorial of n - 1. Throws an exception if n is a negative number.
-const factorial = n => +
Calculates the factorial of a number.
Use recursion. If n is less than or equal to 1, return 1. Otherwise, return the product of n and the factorial of n - 1. Throws an exception if n is a negative number.
const factorial = n => n < 0 ? (() => { throw new TypeError('Negative numbers are not allowed!'); diff --git a/docs/object.html b/docs/object.html index 40d4fa12b..d49b31ba5 100644 --- a/docs/object.html +++ b/docs/object.html @@ -130,8 +130,7 @@ o[0[ 1][0] = 4; // not allowed as well
Assigns default values for all properties in an object that are undefined.
Use Object.assign() to create a new empty object and copy the original one to maintain key order, use Array.prototype.reverse() and the spread operator ... to combine the default values from left to right, finally use obj again to overwrite properties that originally had a value.
const defaults = (obj, ...defs) => Object.assign({}, obj, ...defs.reverse(), obj);
defaults({ a: 1 }, { b: 2 }, { b: 6 }, { a: 3 }); // { a: 1, b: 2 } -
Returns the target value in a nested JSON object, based on the given key.
Use the in operator to check if target exists in obj. If found, return the value of obj[target], otherwise use Object.values(obj) and Array.prototype.reduce() to recursively call dig on each nested object until the first matching key/value pair is found.
-const dig = (obj, target) => +
Returns the target value in a nested JSON object, based on the given key.
Use the in operator to check if target exists in obj. If found, return the value of obj[target], otherwise use Object.values(obj) and Array.prototype.reduce() to recursively call dig on each nested object until the first matching key/value pair is found.
const dig = (obj, target) => target in obj ? obj[target] : Object.values(obj).reduce((acc, val) => { diff --git a/snippets/dig.md b/snippets/dig.md index a349ef2d3..737130b6e 100644 --- a/snippets/dig.md +++ b/snippets/dig.md @@ -6,7 +6,6 @@ Use the `in` operator to check if `target` exists in `obj`. If found, return the value of `obj[target]`, otherwise use `Object.values(obj)` and `Array.prototype.reduce()` to recursively call `dig` on each nested object until the first matching key/value pair is found. ```js - const dig = (obj, target) => target in obj ? obj[target] diff --git a/snippets/factorial.md b/snippets/factorial.md index 2266247b4..cf3acc9cc 100644 --- a/snippets/factorial.md +++ b/snippets/factorial.md @@ -8,7 +8,6 @@ Otherwise, return the product of `n` and the factorial of `n - 1`. Throws an exception if `n` is a negative number. ```js - const factorial = n => n < 0 ? (() => { diff --git a/snippets/pipeAsyncFunctions.md b/snippets/pipeAsyncFunctions.md index 61b850a39..47d6f620c 100644 --- a/snippets/pipeAsyncFunctions.md +++ b/snippets/pipeAsyncFunctions.md @@ -11,7 +11,6 @@ const pipeAsyncFunctions = (...fns) => arg => fns.reduce((p, f) => p.then(f), Pr ``` ```js - const sum = pipeAsyncFunctions( x => x + 1, x => new Promise(resolve => setTimeout(() => resolve(x + 2), 1000)), diff --git a/snippets/remove.md b/snippets/remove.md index 1c457d2d9..58de9c2e0 100644 --- a/snippets/remove.md +++ b/snippets/remove.md @@ -6,7 +6,6 @@ Use `Array.prototype.filter()` to find array elements that return truthy values The `func` is invoked with three arguments (`value, index, array`). ```js - const remove = (arr, func) => Array.isArray(arr) ? arr.filter(func).reduce((acc, val) => { diff --git a/test/_30s.js b/test/_30s.js index 864116948..867e9f1c9 100644 --- a/test/_30s.js +++ b/test/_30s.js @@ -241,7 +241,6 @@ const differenceBy = (a, b, fn) => { return a.filter(x => !s.has(fn(x))); }; const differenceWith = (arr, val, comp) => arr.filter(a => val.findIndex(b => comp(a, b)) === -1); - const dig = (obj, target) => target in obj ? obj[target] @@ -317,7 +316,6 @@ const extendHex = shortHex => .split('') .map(x => x + x) .join(''); - const factorial = n => n < 0 ? (() => { @@ -962,7 +960,6 @@ const reducedFilter = (data, keys, fn) => }, {}) ); const reject = (pred, array) => array.filter((...args) => !pred(...args)); - const remove = (arr, func) => Array.isArray(arr) ? arr.filter(func).reduce((acc, val) => {