The "..." is called a spread operator in javascript. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax https://develope

The "..." is called a spread operator in javascript. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... (In python there is the "*" operator which should be equivalent: [1, 2, *arr]. Array(clicks) instantiate an array of length 'clicks', with its elements undefined. Then "[...Array(clicks)]" takes the above array instance and spreads it as content in another array. Seems redundant and they could've just used Array(clicks).