Changes the `ICommandsMap` type to be a proper map. This can help catch type errors and also gets us closer to being able to disable the tsconfig suppressImplicitAnyIndexErrors workaround

More manual conversion of index based for loops to for-of loops

This new call works as a type guard and can help avoid writing double negations

Avoid either call in cases where we were iterating over the possibly undefined value. Use `|| []` for these

This code pattern indicates that the type should be nullable

We compile using the alwaysStrict flag so these directives are not needed

This part removes most `use strict` directives that are right after the file header

Fixes #12585