c, d) => a + b + c + d const nums = [1, 2] const copied = [...nums] // தΛෳͨ͠ྻΛ࡞ΕΔ const moreNums = [...copied, 5] // [1, 2, 5] sum(...nums, 10) // 18 const obj = { a: 10, b: "foo" } const obj2 = { b: "bar", c: true } // 2ͭҎ্ͷobjectΛmerge͢ΔɻΩʔ͕ॏෳ͍ͯ͠Δ߹ޙʹॻ͍ͨํͰ্ॻ͖͞ΕΔ const merged = { ...obj, ...obj2 } // {a: 10, b: 'bar', c: true} const getUserConfig = (received) => ({ force: false, allowJs: false, ...received, // σϑΥϧτΛ͞Ε͕ͨ͋Ε্ॻ͖͢Δ }) #hatenaintern)*)+ !"