Turn on TypeScript 'strict' compiler option? about mathjax-src HOT 3 OPEN

Thanks for the pointer. It looks like this turns on four things: noImplicitAny, noImplicitThis, alwaysStrict, and strictNullChecks. We already have noImplicitAny enabled, and I don't think noImplicitThis or alwaysStrict would cause us any problems. But I'm not certain about strictNullChecks. I understand the desire to be careful about this, but I suspect it would take some work to make that compile cleanly for us (we do currently use the fact that null is allowed for any type at the moment), if I read this correctly.

I'm curious how this is supposed to be handled. Do you have to use a lot of type | null expressions when dealing with things that could be null (e.g., option lists, or child pointers, and so on)? or is there some better way to manage that?

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I think so - I don't have a ton of experience with it yet. If you already have type aliases set up, you can add | null. After you check for null, Typescript can infer the type is not null, or you can explicitly declare it so with the ! suffix to the type (e.g., string! declares a string | null as nonnullable).

See also "Nullable types" in https://www.typescriptlang.org/docs/handbook/advanced-types.html

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The strict null checking probably does take the most work to satisfy. We haven't turned it on for some of our codebases yet either.

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