In this video, we take a quick look at refactoring usages of Array.prototype.concat to make use of the ES6 array spread operator. For example, we can refactor towards simple append and prepend statements such as
[...array, value] or
[value, ...array] or combine multiple spread operations to achieve insert via
[...leftSide, value, ...rightSide].
[...someArray] can be used to quickly make a shallow copy of an array to avoid mutation for many common array operations.