fix(pluck): fix pluck's catch-all signature for better type safety (#…

…5192) * fix(pluck): fix pluck's catch-all signature for better type safety Change pluck's catch-all signature that is causing troubles when the passed string is not a key in the argument object. Issue: #5188 * fix(pluck): fix signature and tests Correct the signtaure to be accepted by tests and to return unknown in general * fix(pluck): add test case to check type inference
ReactiveX · Jan 20, 2020 · e0c5b7c · e0c5b7c
1 parent 56e7ceb
commit e0c5b7c
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/spec-dtslint/operators/pluck-spec.ts b/spec-dtslint/operators/pluck-spec.ts
@@ -1,4 +1,4 @@
-import { of } from 'rxjs';
+import { of, Observable } from 'rxjs';
 import { pluck } from 'rxjs/operators';
 
 it('should infer correctly', () => {
@@ -41,6 +41,10 @@ it('should accept string only', () => {
   const a = of({ name: 'abc' }).pipe(pluck(1)); // $ExpectError
 });
 
+it('should not infer type from the variable if key doesn\'t exist', () => {
+  const a: Observable<number> = of({ name: 'abc' }).pipe(pluck('xyz')); // $ExpectError
+});
+
 it('should accept a spread of arguments', () => {
   const obj = {
     foo: {

diff --git a/src/internal/operators/pluck.ts b/src/internal/operators/pluck.ts
@@ -9,8 +9,8 @@ export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends
 export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2], K4 extends keyof T[K1][K2][K3]>(k1: K1, k2: K2, k3: K3, k4: K4): OperatorFunction<T, T[K1][K2][K3][K4]>;
 export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2], K4 extends keyof T[K1][K2][K3], K5 extends keyof T[K1][K2][K3][K4]>(k1: K1, k2: K2, k3: K3, k4: K4, k5: K5): OperatorFunction<T, T[K1][K2][K3][K4][K5]>;
 export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2], K4 extends keyof T[K1][K2][K3], K5 extends keyof T[K1][K2][K3][K4], K6 extends keyof T[K1][K2][K3][K4][K5]>(k1: K1, k2: K2, k3: K3, k4: K4, k5: K5, k6: K6): OperatorFunction<T, T[K1][K2][K3][K4][K5][K6]>;
-export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2], K4 extends keyof T[K1][K2][K3], K5 extends keyof T[K1][K2][K3][K4], K6 extends keyof T[K1][K2][K3][K4][K5], R>(k1: K1, k2: K2, k3: K3, k4: K4, k5: K5, k6: K6, ...rest: string[]): OperatorFunction<T, R>;
-export function pluck<T, R= unknown>(...properties: string[]): OperatorFunction<T, R>;
+export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2], K4 extends keyof T[K1][K2][K3], K5 extends keyof T[K1][K2][K3][K4], K6 extends keyof T[K1][K2][K3][K4][K5]>(k1: K1, k2: K2, k3: K3, k4: K4, k5: K5, k6: K6, ...rest: string[]): OperatorFunction<T, unknown>;
+export function pluck<T>(...properties: string[]): OperatorFunction<T, unknown>;
 /* tslint:enable:max-line-length */
 
 /**