Many of the strict checks did not even exist when TS was first created.
Some of these missing checks were why Flow was an attractive choice when weighing [Flow vs Typescript][1].
For example, it wasn't until Typescript 2.0 that we got null checks!
- https://www.typescriptlang.org/docs/handbook/release-notes/t...
function getLength(s: string): number { return s.length; // Runtime crash if s is null/undefined } getLength(null); // TypeScript <2.0 would not error here
Some of these missing checks were why Flow was an attractive choice when weighing [Flow vs Typescript][1].
For example, it wasn't until Typescript 2.0 that we got null checks!
- https://www.typescriptlang.org/docs/handbook/release-notes/t...
[1]: https://djcordhose.github.io/flow-vs-typescript/2016_hhjs.ht...