27 lines
617 B
TypeScript
27 lines
617 B
TypeScript
export function countIf<T>(f: (x: T) => boolean, xs: T[]): number {
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return xs.filter(f).length;
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}
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export function count<T>(x: T, xs: T[]): number {
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return countIf(y => x === y, xs);
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}
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export function concat<T>(xss: T[][]): T[] {
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return ([] as T[]).concat(...xss);
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}
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export function intersperse<T>(sep: T, xs: T[]): T[] {
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return concat(xs.map(x => [sep, x])).slice(1);
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}
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export function erase<T>(x: T, xs: T[]): T[] {
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return xs.filter(y => x !== y);
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}
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export function unique<T>(xs: T[]): T[] {
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return [...new Set(xs)];
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}
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export function sum(xs: number[]): number {
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return xs.reduce((a, b) => a + b, 0);
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}
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