Shouldn't have made an example in the if-statement as it is mostly useless there. But triple ! is very common to negate-and-convert a possibly falsy statement (undefined, null, false/true):

const x: boolean | undefined | null = getValue(); const not_x: boolean = !!!y

I added TS type annotation for clarity, although could be inferred if `getValue` is typed accordingly.

And line breaks after return statement? Is that true? Haven't stumbled on that one. So this is probably misinformation.