@tonaljs/collection
Version:
Utility functions to work with collections (arrays)
64 lines • 1.24 kB
JavaScript
// index.ts
function ascR(b, n) {
const a = [];
for (; n--; a[n] = n + b) ;
return a;
}
function descR(b, n) {
const a = [];
for (; n--; a[n] = b - n) ;
return a;
}
function range(from, to) {
return from < to ? ascR(from, to - from + 1) : descR(from, from - to + 1);
}
function rotate(times, arr) {
const len = arr.length;
const n = (times % len + len) % len;
return arr.slice(n, len).concat(arr.slice(0, n));
}
function compact(arr) {
return arr.filter((n) => n === 0 || n);
}
function shuffle(arr, rnd = Math.random) {
let i;
let t;
let m = arr.length;
while (m) {
i = Math.floor(rnd() * m--);
t = arr[m];
arr[m] = arr[i];
arr[i] = t;
}
return arr;
}
function permutations(arr) {
if (arr.length === 0) {
return [[]];
}
return permutations(arr.slice(1)).reduce((acc, perm) => {
return acc.concat(
arr.map((e, pos) => {
const newPerm = perm.slice();
newPerm.splice(pos, 0, arr[0]);
return newPerm;
})
);
}, []);
}
var collection_default = {
compact,
permutations,
range,
rotate,
shuffle
};
export {
compact,
collection_default as default,
permutations,
range,
rotate,
shuffle
};
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