refactor: refactor throwError operator to use factory function in unit tests and .ts file

[nitinmalave]

…

Description:

• As per docs, throwError accepts factory functions to emit an error and no longer able to accept an error directly. That's why i went ahead and made changes in all unit tests wherever throwError is getting used to accept factory function.

Related issue (if exists):
Noop

[cartant]

I'm okay with the wholesale replacement in the implementation tests, but I think the dtslint tests - spec-dtslint/observables/throwError-spec.ts - need to include both. So, rather than replace the calls in the dtslint tests, copy them and then replace them.

Also, this PR seems to have some conflicts with what's currently in master.

[nitinmalave]

Hi @cartant, i am little confuse here. Can you please help me with what i understood is correct or not?
As per your suggestion,

• changes which needs to be done are in 'dtslint/observables/throwError-spec.ts' file only, right?
• 'dtslint/observables/throwError-spec.ts' should have 2 versions of throwError and is should look like this :

`it('should accept any type and return never observable', () => {
const a = throwError(1); // $ExpectType Observable
const a1 = throwError(() => (1)); // $ExpectType Observable
const b = throwError('a'); // $ExpectType Observable
const b1 = throwError(() => ('a')); // $ExpectType Observable
const c = throwError({a: 1}); // $ExpectType Observable
const c1 = throwError(() => ({ a: 1 })); // $ExpectType Observable
const d = throwError(() => ({ a: 2 })); // $ExpectType Observable
});

it('should support scheduler', () => {
const a = throwError(1, animationFrameScheduler); // $ExpectType Observable
const a1 = throwError(() => (1, animationFrameScheduler)); // $ExpectType Observable
});`

Please correct me if i am wrong.

[cartant]

I'd create separate it functions to make it clearer:

it('should support an error value and a scheduler', () => {
  const a = throwError(1, animationFrameScheduler); // $ExpectType Observable<never>
});`

it('should support a factory and a scheduler', () => {
  const a = throwError(() => 1, animationFrameScheduler); // $ExpectType Observable<never>
});`

Also, you have the parentheses in the wrong place for the last test and that's what's failing in CI.

[nitinmalave]

Got it. Thanks @cartant for quick support. I have committed this changes. Please take a look at it.

[cartant]

LGTM. Thanks.