compact

Returns the truthy values from an array while preserving their order.

Code

compact.ts

export type Falsy = false | 0 | 0n | "" | null | undefined;

const isTruthy = <Value>(value: Value): value is Exclude<Value, Falsy> =>
  Boolean(value);

/** Returns a new array containing only truthy values. */
export const compact = <const T>(
  array: readonly T[],
): Array<Exclude<T, Falsy>> => {
  const result: Array<Exclude<T, Falsy>> = [];
  for (let index = 0; index < array.length; index += 1) {
    if (!Object.hasOwn(array, index)) continue;
    const value = array[index] as T;
    if (isTruthy(value)) result.push(value);
  }
  return result;
};

Download

wget

Terminal

wget -O src/lib/compact.ts https://raw.githubusercontent.com/jrTilak/lazykit/HEAD/registry/functions/compact.ts

degit

Terminal

temp_dir="$(mktemp -d)" && bunx degit jrTilak/lazykit/registry/functions "$temp_dir" && mv "$temp_dir/compact.ts" src/lib/compact.ts && rm -r "$temp_dir"

Examples

compact.example.ts

import { compact } from "./compact";

const mixedArray = [0, 1, false, 2, '', 3, null, undefined, {}, [], [4, 5]];
const result = compact(mixedArray);

console.log(result);
// Output: [1, 2, 3, {}, [], [4, 5]]

compact.2.example.ts

import { compact } from "./compact";

const mixedArray = [0, 1, false, 2, '', 3, null, undefined, {}, [], [4, 5]];
const result = compact(mixedArray);

console.log(result);
// Output: [1, 2, 3, {}, [], [4, 5]]

Props

• array (readonly T[]) — Values to filter. Empty slots and JavaScript falsy values such as false, 0, 0n, "", null, undefined, and NaN are removed.

Returns

Array<Exclude<T, Falsy>> — A new array containing the truthy values.