All files / src/implementation observer.ts

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/**
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import * as type from './type';
 
type NextFn<T> = (value: T) => void;
type ErrorFn = (error: Error) => void;
type CompleteFn = () => void;
type Unsubscribe = () => void;
 
type Subscribe<T> = (
  next: NextFn<T> | { [name: string]: string | null },
  error?: ErrorFn,
  complete?: CompleteFn
) => Unsubscribe;
 
export { NextFn, ErrorFn, CompleteFn, Unsubscribe, Subscribe };
 
/**
 * @struct
 */
export class Observer<T> {
  next: NextFn<T> | null;
  error: ErrorFn | null;
  complete: CompleteFn | null;
 
  constructor(
    nextOrObserver: NextFn<T> | { [name: string]: string | null } | null,
    opt_error?: ErrorFn | null,
    opt_complete?: CompleteFn | null
  ) {
    let asFunctions =
      type.isFunction(nextOrObserver) ||
      type.isDef(opt_error) ||
      type.isDef(opt_complete);
    if (asFunctions) {
      this.next = nextOrObserver as NextFn<T> | null;
      this.error = opt_error || null;
      this.complete = opt_complete || null;
    } else {
      const observer = nextOrObserver as {
        next?: NextFn<T> | null;
        error?: ErrorFn | null;
        complete?: CompleteFn | null;
      };
      this.next = observer.next || null;
      this.error = observer.error || null;
      this.complete = observer.complete || null;
    }
  }
}