tslib VS ts-transform-import-path-rewrite

It's appropriate for software designed for use cases where an attribution requirement would be inconvenient or otherwise undesirable. For example, https://github.com/microsoft/tslib uses it, because that library is automatically included in any TypeScript program that uses downleveling, so if it had an attribution requirement then that requirement would apply to every program written in TypeScript, which nobody wants. (GCC and LLVM do something similar with their special runtime-library exceptions to the GPL and Apache License, respectively, but tslib lives in a separate repository from the rest of TypeScript and so could easily just get a separate license.)

Looking at some popular JavaScript projects on GitHub, I noted that react, moment, and express all use single quotes for strings. However, another popular project, tslib, uses double quotes 🙄. So, while it would seem that single quotes is more common, this metric is not entirely conclusive.

Things get a little interesting if you're using CommonJS interoperability, in which case our second import becomes something like const view2 = __importDefault(require("./view2")).default. This helper function checks to see if the imported file is an ES module and effectively namespaces the module under the default property if not. You can see TypeScript's implementation of this here.

You may just copy them from tslib. It's 0BSD-licensed which doesn't even require attribution; but having the link somewhere in your comments is at least polite 🙂

If you want to have aliases like this, you have to configure it separately, for example, using bable-plugin-module-resolver if you use Babel, or something like this https://github.com/dropbox/ts-transform-import-path-rewrite, or this https://github.com/ilearnio/module-alias