TS type assertions need to be avoided.
The following trivial example demonstrates why
```
type Person = {
name: string;
isBad: boolean;
};
function makePerson(): Person {
const p: Person = {name: 'whatever'} as Person
p.isBad = false
return p // theoretically we are now good, p is a Person
}
```
Should the type ever change though, TS will happily trot along
```
type Person = {
name: string;
isBad: boolean;
omgHowCouldYou: number;
};
function makePerson(): Person {
const p: Person = {name: 'whatever'} as Person
p.isBad = true
return p // p is *not* a Person, omgHowCouldYou is missing
}
```
But we pinky swore to the compiler that p is in fact a Person.
In other words, the types are now wrong and you will fail during
runtime.
