initial commit: scaffolding

1 files changed, 32 insertions, 0 deletions

diff --git a/node_modules/rxjs/src/internal/util/lift.ts b/node_modules/rxjs/src/internal/util/lift.ts
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+++ b/node_modules/rxjs/src/internal/util/lift.ts
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+import { Observable } from '../Observable';
+import { Subscriber } from '../Subscriber';
+import { OperatorFunction } from '../types';
+import { isFunction } from './isFunction';
+
+/**
+ * Used to determine if an object is an Observable with a lift function.
+ */
+export function hasLift(source: any): source is { lift: InstanceType<typeof Observable>['lift'] } {
+  return isFunction(source?.lift);
+}
+
+/**
+ * Creates an `OperatorFunction`. Used to define operators throughout the library in a concise way.
+ * @param init The logic to connect the liftedSource to the subscriber at the moment of subscription.
+ */
+export function operate<T, R>(
+  init: (liftedSource: Observable<T>, subscriber: Subscriber<R>) => (() => void) | void
+): OperatorFunction<T, R> {
+  return (source: Observable<T>) => {
+    if (hasLift(source)) {
+      return source.lift(function (this: Subscriber<R>, liftedSource: Observable<T>) {
+        try {
+          return init(liftedSource, this);
+        } catch (err) {
+          this.error(err);
+        }
+      });
+    }
+    throw new TypeError('Unable to lift unknown Observable type');
+  };
+}