Short code snippets for all your development needs

Start of main content## Recommended snippets

Generates all permutations of an array's elements (contains duplicates).

- Use recursion.
- For each element in the given array, create all the partial permutations for the rest of its elements.
- Use
`Array.prototype.map()`

to combine the element with each partial permutation, then`Array.prototype.reduce()`

to combine all permutations in one array. - Base cases are for
`Array.prototype.length`

equal to`2`

or`1`

. - ⚠️
**WARNING**: This function's execution time increases exponentially with each array element. Anything more than 8 to 10 entries may cause your browser to hang as it tries to solve all the different combinations.

const permutations = arr => { if (arr.length <= 2) return arr.length === 2 ? [arr, [arr[1], arr[0]]] : arr; return arr.reduce( (acc, item, i) => acc.concat( permutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map(val => [ item, ...val, ]) ), [] ); };

permutations([1, 33, 5]); // [ [1, 33, 5], [1, 5, 33], [33, 1, 5], [33, 5, 1], [5, 1, 33], [5, 33, 1] ]

### haveSameContents

JavaScript, Array

Checks if two arrays contain the same elements regardless of order.

### isContainedIn

JavaScript, Array

Checks if the elements of the first array are contained in the second one regardless of order.

### uniqueSymmetricDifference

JavaScript, Array

Returns the unique symmetric difference between two arrays, not containing duplicate values from either array.