[timdumol]

Moving to TypeScript definitely helped us. The move itself revealed a couple undefined variable errors, and static typing has saved us a lot of pain. It was also extremely useful for when we decided to remove a few libraries; the static typing gave us confidence that we didn't miss a few usages.

[nkassis]

My experience as well. The benefits I've seen have been easier refactoring, code completion and I find it faster to implement things with typescript highlighting issues in my editor so that I can correct them before seeing if it runs in a browser.

[dham]

You can catch undefined variables with something like eslint or jshint.