Semicolon Before Square Bracket

Can anyone tell me why yarn format is adding a semi colon before my square brackets. Yarn build fails without it.. ;[ this.querySelector('[class$='-cover'] img'),

Solution 1:

Consider the following (basic) code:

doSomething()
[1].forEach(i => doAnotherThing(i))

Reading it this way, it looks straightforward--call some function, and then iterate over an array and call another function. Two separate steps.

However, JS doesn't look at whitespace. What if you saw the code like this:

doSomething()[1].forEach(i => doAnotherThing(i))

What does that now mean? Now it looks like you need to call doSomething() which returns an array, take item 1 of that array, and hopefully that is an array because we are iterating over it.

As opposed to:

doSomething();[1].forEach(i => doAnotherThing(i))

Which also condenses the whitespace but now is clear that you mean these to be two completely separate steps. The primary reason for prepending with a semicolon like that is to clarify your intentions.