spread (...) operator

Spread operator, Spread syntax

ECMAScript, TypeScript, JavaScript

Spread syntax can be used when all elements from an object or array need to be included in a list of some kind. 

Syntax

For function calls:

myFunction(...iterableObj); // pass all elements of iterableObj as arguments to function myFunction

For array literals:

[...iterableObj, '4', 'five', 6]; // combine two arrays by inserting all elements from iterableObj

For object literals (new in ECMAScript 2018):

let objClone = { ...obj }; // pass all key:value pairs from an object

source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax