Initial project import

node_modules/rxjs/src/internal/operators/pluck.ts

@@ -0,0 +1,106 @@
+import { map } from './map';
+import { OperatorFunction } from '../types';
+
+/* tslint:disable:max-line-length */
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+export function pluck<T, K1 extends keyof T>(k1: K1): OperatorFunction<T, T[K1]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1]>(k1: K1, k2: K2): OperatorFunction<T, T[K1][K2]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+export function pluck<T, K1 extends keyof T, K2 extends keyof T[K1], K3 extends keyof T[K1][K2]>(
+  k1: K1,
+  k2: K2,
+  k3: K3
+): OperatorFunction<T, T[K1][K2][K3]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+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]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+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]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+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]>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+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>;
+/** @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8. */
+export function pluck<T>(...properties: string[]): OperatorFunction<T, unknown>;
+/* tslint:enable:max-line-length */
+
+/**
+ * Maps each source value to its specified nested property.
+ *
+ * <span class="informal">Like {@link map}, but meant only for picking one of
+ * the nested properties of every emitted value.</span>
+ *
+ * ![](pluck.png)
+ *
+ * Given a list of strings or numbers describing a path to a property, retrieves
+ * the value of a specified nested property from all values in the source
+ * Observable. If a property can't be resolved, it will return `undefined` for
+ * that value.
+ *
+ * ## Example
+ *
+ * Map every click to the tagName of the clicked target element
+ *
+ * ```ts
+ * import { fromEvent, pluck } from 'rxjs';
+ *
+ * const clicks = fromEvent(document, 'click');
+ * const tagNames = clicks.pipe(pluck('target', 'tagName'));
+ *
+ * tagNames.subscribe(x => console.log(x));
+ * ```
+ *
+ * @see {@link map}
+ *
+ * @param properties The nested properties to pluck from each source
+ * value.
+ * @return A function that returns an Observable of property values from the
+ * source values.
+ * @deprecated Use {@link map} and optional chaining: `pluck('foo', 'bar')` is `map(x => x?.foo?.bar)`. Will be removed in v8.
+ */
+export function pluck<T, R>(...properties: Array<string | number | symbol>): OperatorFunction<T, R> {
+  const length = properties.length;
+  if (length === 0) {
+    throw new Error('list of properties cannot be empty.');
+  }
+  return map((x) => {
+    let currentProp: any = x;
+    for (let i = 0; i < length; i++) {
+      const p = currentProp?.[properties[i]];
+      if (typeof p !== 'undefined') {
+        currentProp = p;
+      } else {
+        return undefined;
+      }
+    }
+    return currentProp;
+  });
+}