I was quite confused until I realized that Elon wouldn’t have his own handle be “elmo” and the remembered the event with ACTUAL Elmo.

Submitted. Thanks for the heads up.

Not to short-circuit the joke, but in this case, it’s because the valid JavaScript version is…

let a

…and one of TypeScript’s main design goals is to be a superset of JavaScript, that only adds syntax, and doesn’t re-write it.

Beyond that, it’s probably a case of some new language just using what the designer is familiar with.