Variadic Function in Middle Position

assert-variadic.ts

function assertAreEqual(...args: [number, number, ...number[], string]): void {
    const [firstValue, ...remaining] = args.slice(0, args.length - 1) as number[];
    const message = args[args.length - 1] as string;
    for (const value of remaining) {
        if (firstValue !== value) throw new Error(message);
    }
}

assertAreEqual(1, 1, 1, 1, "They're not the same");