diff --git a/README.md b/README.md index d0be53894..ab8d611dd 100644 --- a/README.md +++ b/README.md @@ -136,6 +136,8 @@ average(1, 2, 3); * [`similarity`](#similarity) * [`sortedIndex`](#sortedindex) * [`symmetricDifference`](#symmetricdifference) +* [`symmetricDifferenceBy`](#symmetricdifferenceby) +* [`symmetricDifferenceWith`](#symmetricdifferencewith) * [`tail`](#tail) * [`take`](#take) * [`takeRight`](#takeright) @@ -1744,6 +1746,61 @@ symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4]
[⬆ Back to top](#table-of-contents) +### symmetricDifferenceBy + +Returns the symmetric difference between two arrays, after applying the provided function to each array element of both. + +Create a `Set` by applying `fn` to each array's elements, then use `Array.filter()` on each of them to only keep values not contained in the other. + +```js +const symmetricDifferenceBy = (a, b, fn) => { + const sA = new Set(a.map(v => fn(v))), + sB = new Set(b.map(v => fn(v))); + return [...a.filter(x => !sB.has(fn(x))), ...b.filter(x => !sA.has(fn(x)))]; +}; +``` + +
+Examples + +```js +symmetricDifferenceBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [ 1.2, 3.4 ] +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + +### symmetricDifferenceWith + +Returns the symmetric difference between two arrays, using a provided function as a comparator. + +Use `Array.filter()` and `Array.findIndex()` to find the appropriate values. + +```js +const symmetricDifferenceWith = (arr, val, comp) => [ + ...arr.filter(a => val.findIndex(b => comp(a, b)) === -1), + ...val.filter(a => arr.findIndex(b => comp(a, b)) === -1) +]; +``` + +
+Examples + +```js +symmetricDifferenceWith( + [1, 1.2, 1.5, 3, 0], + [1.9, 3, 0, 3.9], + (a, b) => Math.round(a) === Math.round(b) +); // [1, 1.2, 3.9] +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + ### tail Returns all elements in an array except for the first one. diff --git a/docs/index.html b/docs/index.html index 054980965..815e5ed87 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

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);
+      }
logo 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Adapter
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);
 
Promise.resolve([1, 2, 3])
   .then(call('map', x => 2 * x))
   .then(console.log); //[ 2, 4, 6 ]
@@ -335,6 +335,21 @@ Object.assig
   return [...a.filter(x => !sB.has(x)), ...b.filter(x => !sA.has(x))];
 };
 
symmetricDifference([1, 2, 3], [1, 2, 4]); // [3,4]
+
symmetricDifferenceBy
Returns the symmetric difference between two arrays, after applying the provided function to each array element of both.
Create a Set by applying fn to each array's elements, then use Array.filter() on each of them to only keep values not contained in the other.
const symmetricDifferenceBy = (a, b, fn) => {
+  const sA = new Set(a.map(v => fn(v))),
+    sB = new Set(b.map(v => fn(v)));
+  return [...a.filter(x => !sB.has(fn(x))), ...b.filter(x => !sA.has(fn(x)))];
+};
+
symmetricDifferenceBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [ 1.2, 3.4 ]
+
symmetricDifferenceWith
Returns the symmetric difference between two arrays, using a provided function as a comparator.
Use Array.filter() and Array.findIndex() to find the appropriate values.
const symmetricDifferenceWith = (arr, val, comp) => [
+  ...arr.filter(a => val.findIndex(b => comp(a, b)) === -1),
+  ...val.filter(a => arr.findIndex(b => comp(a, b)) === -1)
+];
+
symmetricDifferenceWith(
+  [1, 1.2, 1.5, 3, 0],
+  [1.9, 3, 0, 3.9],
+  (a, b) => Math.round(a) === Math.round(b)
+); // [1, 1.2, 3.9]
 
tail
Returns all elements in an array except for the first one.
Return Array.slice(1) if the array's length is more than 1, otherwise, return the whole array.
const tail = arr => (arr.length > 1 ? arr.slice(1) : arr);
 
tail([1, 2, 3]); // [2,3]
 tail([1]); // [1]
diff --git a/snippets/symmetricDifferenceWith.md b/snippets/symmetricDifferenceWith.md
index 67d081ccd..5eab574fa 100644
--- a/snippets/symmetricDifferenceWith.md
+++ b/snippets/symmetricDifferenceWith.md
@@ -7,10 +7,14 @@ Use `Array.filter()` and `Array.findIndex()` to find the appropriate values.
 ```js
 const symmetricDifferenceWith = (arr, val, comp) => [
   ...arr.filter(a => val.findIndex(b => comp(a, b)) === -1),
-  ...val.filter(a => arr.findIndex(b => comp(a, b)) === -1),
+  ...val.filter(a => arr.findIndex(b => comp(a, b)) === -1)
 ];
 ```
 
 ```js
-symmetricDifferenceWith([1, 1.2, 1.5, 3, 0], [1.9, 3, 0, 3.9], (a, b) => Math.round(a) === Math.round(b)); // [1, 1.2, 3.9]
+symmetricDifferenceWith(
+  [1, 1.2, 1.5, 3, 0],
+  [1.9, 3, 0, 3.9],
+  (a, b) => Math.round(a) === Math.round(b)
+); // [1, 1.2, 3.9]
 ```