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node_modules/rxjs/_esm5/operator/defaultIfEmpty.js

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+/** PURE_IMPORTS_START .._operators_defaultIfEmpty PURE_IMPORTS_END */
+import { defaultIfEmpty as higherOrder } from '../operators/defaultIfEmpty';
+/* tslint:enable:max-line-length */
+/**
+ * Emits a given value if the source Observable completes without emitting any
+ * `next` value, otherwise mirrors the source Observable.
+ *
+ * <span class="informal">If the source Observable turns out to be empty, then
+ * this operator will emit a default value.</span>
+ *
+ * <img src="./img/defaultIfEmpty.png" width="100%">
+ *
+ * `defaultIfEmpty` emits the values emitted by the source Observable or a
+ * specified default value if the source Observable is empty (completes without
+ * having emitted any `next` value).
+ *
+ * @example <caption>If no clicks happen in 5 seconds, then emit "no clicks"</caption>
+ * var clicks = Rx.Observable.fromEvent(document, 'click');
+ * var clicksBeforeFive = clicks.takeUntil(Rx.Observable.interval(5000));
+ * var result = clicksBeforeFive.defaultIfEmpty('no clicks');
+ * result.subscribe(x => console.log(x));
+ *
+ * @see {@link empty}
+ * @see {@link last}
+ *
+ * @param {any} [defaultValue=null] The default value used if the source
+ * Observable is empty.
+ * @return {Observable} An Observable that emits either the specified
+ * `defaultValue` if the source Observable emits no items, or the values emitted
+ * by the source Observable.
+ * @method defaultIfEmpty
+ * @owner Observable
+ */
+export function defaultIfEmpty(defaultValue) {
+    if (defaultValue === void 0) {
+        defaultValue = null;
+    }
+    return higherOrder(defaultValue)(this);
+}
+//# sourceMappingURL=defaultIfEmpty.js.map