hunk.code_window: export default function publish() {
     return multicast.call(this, subjectFactory);
   }
  
hunk.labels: keep replace keep
hunk.after_edit:   return multicast.call(this, new Subject());
  
hunk.file_path: src/operators/publish.ts
hunk.type: replace
file: import Operator from '../Operator';
  import Subscriber from '../Subscriber';
  
  import tryCatch from '../util/tryCatch';
  import {errorObject} from '../util/errorObject';
  import bindCallback from '../util/bindCallback';
  
  export default function distinctUntilChanged<T>(compare?: (x: T, y: T) => boolean, thisArg?: any) {
    return this.lift(new DistinctUntilChangedOperator(thisArg ?
      <(x: T, y: T) => boolean> bindCallback(compare, thisArg, 2) :
      compare));
  }
  
  class DistinctUntilChangedOperator<T, R> implements Operator<T, R> {
  
    compare: (x: T, y: T) => boolean;
  
    constructor(compare?: (x: T, y: T) => boolean) {
      this.compare = compare;
    }
  
    call(subscriber: Subscriber<T>): Subscriber<T> {
      return new DistinctUntilChangedSubscriber(subscriber, this.compare);
    }
  }
  
  class DistinctUntilChangedSubscriber<T> extends Subscriber<T> {
  
    value: T;
    hasValue: boolean = false;
  
    constructor(destination: Subscriber<T>, compare?: (x: T, y: T) => boolean) {
      super(destination);
      if (typeof compare === 'function') {
        this.compare = compare;
      }
    }
  
    compare(x: T, y: T) {
      return x === y;
    }
  
    _next(x) {
  
      let result: any = false;
  
      if (this.hasValue) {
        result = tryCatch(this.compare)(this.value, x);
        if (result === errorObject) {
          this.destination.error(errorObject.e);
          return;
        }
      } else {
        this.hasValue = true;
      }
  
      if (Boolean(result) === false) {
        this.value = x;
        this.destination.next(x);
      }
    }
  }
  