add flatten array util

Author: s1gr1d

packages/utils/src/array.ts

@@ -0,0 +1,19 @@
+export type NestedArray<T> = Array<NestedArray<T> | T>;
+
+/** Flattens a multi-dimensional array */
+export function flatten<T>(input: NestedArray<T>): T[] {
+  const result: T[] = [];
+
+  const flattenHelper = (input: NestedArray<T>): void => {
+    input.forEach((el: T | NestedArray<T>) => {
+      if (Array.isArray(el)) {
+        flattenHelper(el as NestedArray<T>);
+      } else {
+        result.push(el as T);
+      }
+    });
+  };
+
+  flattenHelper(input);
+  return result;
+}

packages/utils/src/index.ts

@@ -1,4 +1,5 @@
 export * from './aggregate-errors';
+export * from './array';
 export * from './browser';
 export * from './dsn';
 export * from './error';

packages/utils/test/array.test.ts

@@ -0,0 +1,58 @@
+import type { NestedArray } from '../src/array';
+import { flatten } from '../src/array';
+
+describe('flatten', () => {
+  it('should return the same array when input is a flat array', () => {
+    const input = [1, 2, 3, 4];
+    const expected = [1, 2, 3, 4];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should flatten a nested array of numbers', () => {
+    const input = [[1, 2, [3]], 4];
+    const expected = [1, 2, 3, 4];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should flatten a nested array of strings', () => {
+    const input = [
+      ['Hello', 'World'],
+      ['How', 'Are', 'You'],
+    ];
+    const expected = ['Hello', 'World', 'How', 'Are', 'You'];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should flatten a nested array of objects', () => {
+    const input: NestedArray<{ a: number; b?: number } | { b: number; a?: number }> = [
+      [{ a: 1 }, { b: 2 }],
+      [{ a: 3 }, { b: 4 }],
+    ];
+    const expected = [{ a: 1 }, { b: 2 }, { a: 3 }, { b: 4 }];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should flatten a mixed type array', () => {
+    const input: NestedArray<string | { b: number }> = [['a', { b: 2 }, 'c'], 'd'];
+    const expected = ['a', { b: 2 }, 'c', 'd'];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should flatten a deeply nested array', () => {
+    const input = [1, [2, [3, [4, [5]]]]];
+    const expected = [1, 2, 3, 4, 5];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should return an empty array when input is empty', () => {
+    const input: any[] = [];
+    const expected: any[] = [];
+    expect(flatten(input)).toEqual(expected);
+  });
+
+  it('should return the same array when input is a flat array', () => {
+    const input = [1, 'a', { b: 2 }, 'c', 3];
+    const expected = [1, 'a', { b: 2 }, 'c', 3];
+    expect(flatten(input)).toEqual(expected);
+  });
+});