23 lines
531 B
TypeScript
23 lines
531 B
TypeScript
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);
|
|
}
|
|
|
|
export function concat<T>(xss: T[][]): T[] {
|
|
return ([] as T[]).concat(...xss);
|
|
}
|
|
|
|
export function intersperse<T>(sep: T, xs: T[]): T[] {
|
|
return concat(xs.map(x => [sep, x])).slice(1);
|
|
}
|
|
|
|
export function erase<T>(x: T, xs: T[]): T[] {
|
|
return xs.filter(y => x !== y);
|
|
}
|
|
|
|
export function unique<T>(xs: T[]): T[] {
|
|
return [...new Set(xs)];
|
|
}
|