directus/packages/shared/src/utils/move-in-array.ts

export function moveInArray<T = any>(array: T[], fromIndex: number, toIndex: number): T[] {
	const item = array[fromIndex];
	const length = array.length;
	const diff = fromIndex - toIndex;

	if (item === undefined) return array;

	if (diff > 0) {
		// move left
		return [
			...array.slice(0, toIndex),
			item,
			...array.slice(toIndex, fromIndex),
			...array.slice(fromIndex + 1, length),
		];
	} else if (diff < 0) {
		// move right
		const targetIndex = toIndex + 1;
		return [
			...array.slice(0, fromIndex),
			...array.slice(fromIndex + 1, targetIndex),
			item,
			...array.slice(targetIndex, length),
		];
	}

	return array;
}