calckey/src/prelude/array.ts

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2018-09-05 17:16:08 +00:00
export function countIf<T>(f: (x: T) => boolean, xs: T[]): number {
return xs.filter(f).length;
}
export function count<T>(x: T, xs: T[]): number {
return countIf(y => x === y, xs);
}
2018-09-05 17:28:04 +00:00
export function intersperse<T>(sep: T, xs: T[]): T[] {
return [].concat(...xs.map(x => [sep, x])).slice(1);
}