hunk.code_window: import { Observable } from '../../Observable';
   import { _catch, CatchSignature } from '../../operator/catch';
   Observable.prototype.catch = _catch;
   declare module '../../Observable' {
     interface Observable<T> {
       catch: CatchSignature<T>;
  
hunk.labels: keep keep keep add keep keep keep keep
hunk.after_edit: Observable.prototype._catch = _catch;
  
hunk.file_path: src/add/operator/catch.ts
hunk.type: add
file: define('perf-helpers', ['exports'], function (exports) {
    exports.printLn = function () {
      var args = [].slice.call(arguments);
      var p = document.createElement('p');
      p.innerText = args.map(function (x) {
        if (typeof x === 'object') {
          return JSON.stringify(x, null, 2);
        }
        return x.toString();
      }).join(' ');
  
      document.body.appendChild(p);
      window.console.log.apply(window.console, args);
    };
  });