[jmkni]

This is only a recent addition to Typescript as well.

I'm working on a project built on Angular7 at the moment, and the version of Typescript we use is too old for this operator.

What happens when the browser supports an operator the version of Typescript you are using doesn't?

[untog]

> What happens when the browser supports an operator the version of Typescript you are using doesn't?

Nothing, because the compiled TypeScript won't contain it. TypeScript is deliberately conservative about the language features it supports to ensure it never gets out of sync with JS.

[jve]

> What happens when the browser supports an operator the version of Typescript you are using doesn't?

Well I'm certain that it won't compile. Your .ts file must go through tsc after all before you get .js