feat(TS): Update to TypeScript 3.5.3

- Uses `unknown` type instead of `{}` per TS 3
- Updates dtslint tests where certain things are now working better

BREAKING CHANGE: RxJS requires TS 3.5

package.json

@@ -137,11 +137,11 @@
     "check-side-effects": "0.0.20",
     "color": "3.0.0",
     "colors": "1.1.2",
-    "commitizen": "^3.1.1",
+    "commitizen": "^4.0.3",
     "cross-env": "5.1.3",
     "cz-conventional-changelog": "1.2.0",
-    "dependency-cruiser": "^4.17.0",
-    "dtslint": "0.7.4",
+    "dependency-cruiser": "^4.27.3",
+    "dtslint": "^0.7.4",
     "escape-string-regexp": "1.0.5",
     "eslint": "4.17.0",
     "eslint-plugin-jasmine": "^2.10.1",
@@ -152,8 +152,8 @@
     "google-closure-compiler-js": "20170218.0.0",
     "gzip-size": "4.1.0",
     "klaw-sync": "3.0.2",
-    "lint-staged": "^9.2.5",
-    "lodash": "^4.17.11",
+    "lint-staged": "^8.1.6",
+    "lodash": "^4.17.15",
     "minimist": "1.2.0",
     "mkdirp": "0.5.1",
     "mocha": "5.0.0",
@@ -177,7 +177,7 @@
     "tslint-etc": "1.5.0",
     "tslint-no-toplevel-property-access": "0.0.2",
     "tslint-no-unused-expression-chai": "0.0.3",
-    "typescript": "^3.0.1",
+    "typescript": "3.5.3",
     "validate-commit-msg": "2.14.0",
     "webpack": "^4.31.0"
   },

spec-dtslint/Observable-spec.ts

@@ -74,8 +74,8 @@ describe('pipe', () => {
     const o = of('foo').pipe(a('1'), a('2'), a('3'), a('4'), a('5'), a('6'), a('7'), a('8'), a('9')); // $ExpectType Observable<"9">
   });
 
-  it('should infer {} for more than 9 arguments', () => {
-    const o = of('foo').pipe(a('1'), a('2'), a('3'), a('4'), a('5'), a('6'), a('7'), a('8'), a('9'), a('10')); // $ExpectType Observable<{}>
+  it('should infer unknown for more than 9 arguments', () => {
+    const o = of('foo').pipe(a('1'), a('2'), a('3'), a('4'), a('5'), a('6'), a('7'), a('8'), a('9'), a('10')); // $ExpectType Observable<unknown>
   });
 
   it('should require a type assertion for more than 9 arguments', () => {
@@ -119,7 +119,7 @@ describe('pipe', () => {
   });
 
   it('should not enforce types beyond the 9th argument', () => {
-    const o = of('foo').pipe(a('1'), a('2'), a('3'), a('4'), a('5'), a('6'), a('7'), a('8'), a('9'), a('#', '10')); // $ExpectType Observable<{}>
+    const o = of('foo').pipe(a('1'), a('2'), a('3'), a('4'), a('5'), a('6'), a('7'), a('8'), a('9'), a('#', '10')); // $ExpectType Observable<unknown>
   });
 
   it('should support operators that return generics', () => {

spec-dtslint/observables/combineLatest-spec.ts

@@ -40,8 +40,8 @@ it('should accept 6 params', () => {
   const o = combineLatest(a, b, c, d, e, f); // $ExpectType Observable<[A, B, C, D, E, F]>
 });
 
-it('should result in Observable<{}> for 7 or more params', () => {
-  const o = combineLatest(a, b, c, d, e, f, g); // $ExpectType Observable<{}>
+it('should result in Observable<unknown> for 7 or more params', () => {
+  const o = combineLatest(a, b, c, d, e, f, g); // $ExpectType Observable<unknown>
 });
 
 it('should accept union types', () => {

spec-dtslint/observables/concat-spec.ts

@@ -28,8 +28,8 @@ it('should accept more than 6 params', () => {
   const o = concat(of(1), of(2), of(3), of(4), of(5), of(6), of(7), of(8), of(9)); // $ExpectType Observable<number>
 });
 
-it('should return Observable<{}> for more than 6 different types of params', () => {
-  const o = concat(of(1), of('a'), of(2), of(true), of(3), of([1, 2, 3]), of(4)); // $ExpectType Observable<{}>
+it('should return Observable<unknown> for more than 6 different types of params', () => {
+  const o = concat(of(1), of('a'), of(2), of(true), of(3), of([1, 2, 3]), of(4)); // $ExpectType Observable<unknown>
 });
 
 it('should accept scheduler after params', () => {

spec-dtslint/observables/race-spec.ts

@@ -47,14 +47,14 @@ describe('race(a, b, c)', () => {
     const o = race(a, a, a, a, a, a, a, a, a, a, a, a, a, a); // $ExpectType Observable<number>
   });
 
-  it('should return {} for 6 or more arguments of different types', () => {
+  it('should return unknown for 6 or more arguments of different types', () => {
     const a = of(1);
     const b = of('a');
     const c = of(true);
     const d = of([1, 2, 3]);
     const e = of(['blah']);
     const f = of({ foo: 'bar' });
-    const o = race(a, b, c, d, e, f); // $ExpectType Observable<{}>
+    const o = race(a, b, c, d, e, f); // $ExpectType Observable<unknown>
   });
 });
 
@@ -107,7 +107,7 @@ describe('race([a, b, c])', () => {
     const d = of([1, 2, 3]);
     const e = of(['blah']);
     const f = of({ foo: 'bar' });
-    const o = race([a, b, c, d, e, f]); // $ExpectType Observable<{}>
+    const o = race([a, b, c, d, e, f]); // $ExpectType Observable<unknown>
   });
 });
 

spec-dtslint/operators/distinct-spec.ts

@@ -7,7 +7,7 @@ it('should infer correctly', () => {
 
 it('should accept a keySelector', () => {
   interface Person { name: string; }
-  const o = of<Person>({ name: 'Tim' }).pipe(distinct(person => person.name)); // $ExpectType Observable<Person>
+  const o = of({ name: 'Tim' } as Person).pipe(distinct(person => person.name)); // $ExpectType Observable<Person>
 });
 
 it('should accept flushes', () => {

spec-dtslint/operators/filter-spec.ts

@@ -55,5 +55,5 @@ it('should support inference from a return type with Boolean as a predicate', ()
   }
 
   const i$: Observable<I> = of();
-  const s$: Observable<string> = i$.pipe(map(i => i.a), filter(Boolean)); // $ExpectType Observable<string>
+  const s$ = i$.pipe(map(i => i.a), filter(Boolean)); // $ExpectType Observable<string>
 });

spec-dtslint/operators/onErrorResumeNext-spec.ts

@@ -43,7 +43,7 @@ it('should accept six inputs', () => {
 });
 
 it('should accept seven and more inputs', () => {
-  const o = of('apple', 'banana', 'peach').pipe(onErrorResumeNext(of(1), of(2), of('3'), of('4'), of(5), of('6'), of(7))); // $ExpectType Observable<string | {}>
+  const o = of('apple', 'banana', 'peach').pipe(onErrorResumeNext(of(1), of(2), of('3'), of('4'), of(5), of('6'), of(7))); // $ExpectType Observable<unknown>
   const p = of('apple', 'banana', 'peach').pipe(onErrorResumeNext<string, string | number>(of(1), of(2), of('3'), of('4'), of(5), of('6'), of(7))); // $ExpectType Observable<string | number>
 });
 

spec-dtslint/operators/pluck-spec.ts

@@ -26,7 +26,7 @@ it('should support nested object of 6 layer depth', () => {
 });
 
 it('should support nested object of more than 6 layer depth', () => {
-  const a = of({ a: { b: { c: { d: { e: { f: { name: 'abc' } } } } } } }).pipe(pluck('a', 'b', 'c', 'd', 'e', 'f', 'name')); // $ExpectType Observable<{}>
+  const a = of({ a: { b: { c: { d: { e: { f: { name: 'abc' } } } } } } }).pipe(pluck('a', 'b', 'c', 'd', 'e', 'f', 'name')); // $ExpectType Observable<unknown>
 });
 
 it('should accept existing keys only', () => {

spec-dtslint/operators/publish-spec.ts

@@ -2,11 +2,7 @@ import { of, Observable } from 'rxjs';
 import { publish } from 'rxjs/operators';
 
 it('should support empty parameter', () => {
-  // Here, TypeScript versions 3.1 and earlier infer Observable<any>. However,
-  // the next version infers Observable<number>. It's not possible to specify
-  // an upper bound for the TypeScript version used by dtslint, so an
-  // expectation cannot be applied.
-  const a = of(1, 2, 3).pipe(publish()); // $ExpectType Observable<any>
+  const a = of(1, 2, 3).pipe(publish()); // $ExpectType Observable<number>
 });
 
 it('should infer when type is specified', () => {

spec-dtslint/operators/publishLast-spec.ts

@@ -2,11 +2,7 @@ import { of } from 'rxjs';
 import { publishLast } from 'rxjs/operators';
 
 it('should accept empty parameter', () => {
-  // Here, TypeScript versions 3.1 and earlier infer Observable<any>. However,
-  // the next version infers Observable<number>. It's not possible to specify
-  // an upper bound for the TypeScript version used by dtslint, so an
-  // expectation cannot be applied.
-  const a = of(1, 2, 3).pipe(publishLast()); // $ExpectType Observable<any>
+  const a = of(1, 2, 3).pipe(publishLast()); // $ExpectType Observable<number>
 });
 
 it('should infer when type is specified', () => {

spec-dtslint/operators/reduce-spec.ts

@@ -31,9 +31,8 @@ it('should accept seed parameter of a different type', () => {
 });
 
 it('should act appropriately with no seed', () => {
-  // Because an observable of one value will just pass that value directly through the reducer,
-  // the below could be a number or a string.
-  const a = of(1, 2, 3).pipe(reduce((a: any, v) => '' + v)); // $ExpectType Observable<string | number>
+  // Starting in TS 3.5, the return type is inferred from the accumulator's type if it's provided without a seed.
+  const a = of(1, 2, 3).pipe(reduce((a: any, v) => '' + v)); // $ExpectType Observable<any>
   const b = of(1, 2, 3).pipe(reduce((a, v) => v)); // $ExpectType Observable<number>
   const c = of(1, 2, 3).pipe(reduce(() => {})); // $ExpectType Observable<number | void>
 });

spec-dtslint/operators/scan-spec.ts

@@ -31,9 +31,8 @@ it('should accept seed parameter of a different type', () => {
 });
 
 it('should act appropriately with no seed', () => {
-  // Because an observable of one value will just pass that value directly through the reducer,
-  // the below could be a number or a string.
-  const a = of(1, 2, 3).pipe(scan((a: any, v) => '' + v)); // $ExpectType Observable<string | number>
+  // Starting in TS 3.5, the return type is inferred from the accumulator's type if it's provided without a seed.
+  const a = of(1, 2, 3).pipe(scan((a: any, v) => '' + v)); // $ExpectType Observable<any>
   const b = of(1, 2, 3).pipe(scan((a, v) => v)); // $ExpectType Observable<number>
   const c = of(1, 2, 3).pipe(scan(() => {})); // $ExpectType Observable<number | void>
 });

spec-dtslint/operators/withLatestFrom-spec.ts

@@ -51,7 +51,7 @@ describe('withLatestFrom', () => {
       const e = of('j', 'k', 'l');
       const f = of('m', 'n', 'o');
       const g = of('p', 'q', 'r');
-      const res = a.pipe(withLatestFrom(b, c, d, e, f, g)); // $ExpectType Observable<{}>
+      const res = a.pipe(withLatestFrom(b, c, d, e, f, g)); // $ExpectType Observable<unknown>
     });
   });
 

spec-dtslint/operators/zip-spec.ts

@@ -4,7 +4,7 @@ import { zip } from 'rxjs/operators';
 it('should support rest parameter observables', () => {
   const o = of(1); // $ExpectType Observable<number>
   const z = [of(2)]; // $ExpectType Observable<number>[]
-  const a = o.pipe(zip(...z)); // $ExpectType Observable<{}>
+  const a = o.pipe(zip(...z)); // $ExpectType Observable<unknown>
 });
 
 it('should support rest parameter observables with type parameters', () => {

spec-dtslint/util/pipe-spec.ts

@@ -21,8 +21,8 @@ function a<I extends string, O extends string>(input: I, output: O): UnaryFuncti
   return i => output;
 }
 
-it('should infer {} for no arguments', () => {
-  const o = pipe(); // $ExpectType UnaryFunction<{}, {}>
+it('should infer unknown for no arguments', () => {
+  const o = pipe(); // $ExpectType UnaryFunction<unknown, unknown>
 });
 
 it('should infer for 1 argument', () => {
@@ -115,12 +115,12 @@ it('should return an explicit Observable type', () => {
   const o = of('foo').pipe(staticPipe); // $ExpectType Observable<string>
 });
 
-it('should return Observable<{}> when T cannot be inferred', () => {
+it('should return Observable<unknown> when T cannot be inferred', () => {
   const customOperator = <T>() => (a: Observable<T>) => a;
 
-  // type can't be possibly be inferred here, so it's {} instead of T.
+  // type can't be possibly be inferred here
   const staticPipe = pipe(customOperator());
-  const o = of('foo').pipe(staticPipe); // $ExpectType Observable<{}>
+  const o = of('foo').pipe(staticPipe); // $ExpectType Observable<unknown>
 });
 
 it('should return a non-narrowed type', () => {

src/internal/Observable.ts

@@ -315,7 +315,7 @@ export class Observable<T> implements Subscribable<T> {
   pipe<A, B, C, D, E, F, G>(op1: OperatorFunction<T, A>, op2: OperatorFunction<A, B>, op3: OperatorFunction<B, C>, op4: OperatorFunction<C, D>, op5: OperatorFunction<D, E>, op6: OperatorFunction<E, F>, op7: OperatorFunction<F, G>): Observable<G>;
   pipe<A, B, C, D, E, F, G, H>(op1: OperatorFunction<T, A>, op2: OperatorFunction<A, B>, op3: OperatorFunction<B, C>, op4: OperatorFunction<C, D>, op5: OperatorFunction<D, E>, op6: OperatorFunction<E, F>, op7: OperatorFunction<F, G>, op8: OperatorFunction<G, H>): Observable<H>;
   pipe<A, B, C, D, E, F, G, H, I>(op1: OperatorFunction<T, A>, op2: OperatorFunction<A, B>, op3: OperatorFunction<B, C>, op4: OperatorFunction<C, D>, op5: OperatorFunction<D, E>, op6: OperatorFunction<E, F>, op7: OperatorFunction<F, G>, op8: OperatorFunction<G, H>, op9: OperatorFunction<H, I>): Observable<I>;
-  pipe<A, B, C, D, E, F, G, H, I>(op1: OperatorFunction<T, A>, op2: OperatorFunction<A, B>, op3: OperatorFunction<B, C>, op4: OperatorFunction<C, D>, op5: OperatorFunction<D, E>, op6: OperatorFunction<E, F>, op7: OperatorFunction<F, G>, op8: OperatorFunction<G, H>, op9: OperatorFunction<H, I>, ...operations: OperatorFunction<any, any>[]): Observable<{}>;
+  pipe<A, B, C, D, E, F, G, H, I>(op1: OperatorFunction<T, A>, op2: OperatorFunction<A, B>, op3: OperatorFunction<B, C>, op4: OperatorFunction<C, D>, op5: OperatorFunction<D, E>, op6: OperatorFunction<E, F>, op7: OperatorFunction<F, G>, op8: OperatorFunction<G, H>, op9: OperatorFunction<H, I>, ...operations: OperatorFunction<any, any>[]): Observable<unknown>;
   /* tslint:enable:max-line-length */
 
   /**

src/internal/observable/race.ts

@@ -16,7 +16,7 @@ export function race<A, B, C>(arg: [ObservableInput<A>, ObservableInput<B>, Obse
 export function race<A, B, C, D>(arg: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>]): Observable<A | B | C | D>;
 export function race<A, B, C, D, E>(arg: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>, ObservableInput<E>]): Observable<A | B | C | D | E>;
 export function race<T>(arg: ObservableInput<T>[]): Observable<T>;
-export function race(arg: ObservableInput<any>[]): Observable<{}>;
+export function race(arg: ObservableInput<any>[]): Observable<unknown>;
 
 export function race<A>(a: ObservableInput<A>): Observable<A>;
 export function race<A, B>(a: ObservableInput<A>, b: ObservableInput<B>): Observable<A | B>;
@@ -26,9 +26,9 @@ export function race<A, B, C, D, E>(a: ObservableInput<A>, b: ObservableInput<B>
 // tslint:enable:max-line-length
 
 export function race<T>(observables: ObservableInput<T>[]): Observable<T>;
-export function race(observables: ObservableInput<any>[]): Observable<{}>;
+export function race(observables: ObservableInput<any>[]): Observable<unknown>;
 export function race<T>(...observables: ObservableInput<T>[]): Observable<T>;
-export function race(...observables: ObservableInput<any>[]): Observable<{}>;
+export function race(...observables: ObservableInput<any>[]): Observable<unknown>;
 
 /**
  * Returns an Observable that mirrors the first source Observable to emit an item.