Code coverage report for src/operator/find.ts

Statements: 100% (43 / 43)      Branches: 100% (12 / 12)      Functions: 100% (9 / 9)      Lines: 100% (38 / 38)      Ignored: none     

All files » src/operator/ » find.ts
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import {Observable} from '../Observable';
import {Operator} from '../Operator';
import {Subscriber} from '../Subscriber';
import {tryCatch} from '../util/tryCatch';
import {errorObject} from '../util/errorObject';
 
/**
 * Returns an Observable that searches for the first item in the source Observable that
 * matches the specified condition, and returns the first occurence in the source.
 * @param {function} predicate function called with each item to test for condition matching.
 * @returns {Observable} an Observable of the first item that matches the condition.
 */
export function find<T>(predicate: (value: T, index: number, source: Observable<T>) => boolean, thisArg?: any): Observable<T> {
  if (typeof predicate !== 'function') {
    throw new TypeError('predicate is not a function');
  }
  return this.lift(new FindValueOperator(predicate, this, false, thisArg));
}
 
export class FindValueOperator<T> implements Operator<T, T> {
  constructor(private predicate: (value: T, index: number, source: Observable<T>) => boolean,
              private source: Observable<T>,
              private yieldIndex: boolean,
              private thisArg?: any) {
  }
 
  call(observer: Subscriber<T>): Subscriber<T> {
    return new FindValueSubscriber(observer, this.predicate, this.source, this.yieldIndex, this.thisArg);
  }
}
 
export class FindValueSubscriber<T> extends Subscriber<T> {
  private index: number = 0;
 
  constructor(destination: Subscriber<T>,
              private predicate: (value: T, index: number, source: Observable<T>) => boolean,
              private source: Observable<T>,
              private yieldIndex: boolean,
              private thisArg?: any) {
    super(destination);
  }
 
  private notifyComplete(value: any): void {
    const destination = this.destination;
 
    destination.next(value);
    destination.complete();
  }
 
  protected _next(value: T): void {
    const { predicate, thisArg } = this;
    const index = this.index++;
    const result = tryCatch(predicate).call(thisArg || this, value, index, this.source);
    if (result === errorObject) {
      this.destination.error(result.e);
    } else if (result) {
      this.notifyComplete(this.yieldIndex ? index : value);
    }
  }
 
  protected _complete(): void {
    this.notifyComplete(this.yieldIndex ? -1 : undefined);
  }
}