Spread Syntax
The Spread
syntax ...
is a relatively new operator that was introduced in ES2018. It provides a concise way to combine objects and arrays.
const obj = {
foo: 1,
bar: 2,
baz: 3
};
const newObj = {
foo: 4,
...obj,
};
console.log(newObj); // { foo: 1, bar: 2, baz: 3 } the old foo is overwritten
It’s also useful for combining arrays.
const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arr3 = [...arr1, ...arr2];
// arr3 will be [1,2,3,4,5,6]