Checks if there are no duplicate values. :package: :smiley_cat: :running: :vhs: :moon: :scroll: :newspaper: :blue_book:

Similar: isUnique, isDisjoint, intersection.

This is part of package extra-array.

array.isUnique(x, [fc], [fm]);
// x:  an array
// fc: compare function (a, b)
// fm: map function (v, i, x)

:stopwatch: Compare function => O(n²).

const array = require("extra-array");

var x = [1, 2, -1, -2];
array.isUnique(x);
// true

array.isUnique(x, (a, b) => Math.abs(a) - Math.abs(b));
// false

array.isUnique(x, null, v => Math.abs(v));
// false

References

• Data.List.Unique.isUnique: Haskell
• List-Extra.allDifferent: elm
• List-Extra.allDifferentBy: elm
• is-iterable-uniq: @Richienb