Cannot read property 'prototype' of undefined (Protractor 4 upgrade problem)

[alecxe]

After upgrading to Protractor 4.0.0, we are starting to see out tests failing immediately in onPrepare() with:

Error: TypeError: Cannot read property 'prototype' of undefined

failing on the following line:

protractor.ElementArrayFinder.prototype.takewhile = function(whileFn) {
   // ...
};

(here we are adding takewhile - linking #2521)

Looks like ElementArrayFinder is no longer exposed on the protractor global object.

How can we extend ElementArrayFinder in Protractor 4? Thanks!

SO reference: http://stackoverflow.com/questions/38380465/cannot-read-property-prototype-of-undefined-after-upgrading-to-protractor-4.

[juliemr]

You can access it via protractor/built/element.

@cnishina thoughts on whether this should be re-introduced to the protractor namespace?

[Droogans]

@alecxe I've had some good success with this approach: #3359 (comment)

[cnishina]

I think we could reintroduce similar to the suggestion / how we export selenium-webdriver stuff:

  // Export the protractor classes
  export let Browser = require('./browser').Browser;
  export let ElementFinder = require('./element').ElementFinder;
  export let ElementArrayFinder = require('./element').ElementArrayFinder;
  export let ElementHelper = require('./browser').ElementHelper;
  export let ProtractorBy = require('./locators').ProtractorBy;
  export let ProtractorExpectedConditions = require('./expectedConditions').ProtractorExpectedConditions;

[philjones88]

@cnishina thanks for putting that PR in. Suffering the same issue here failing 7 of our protractor tests, upgraded from 3.3.0 but don't really want to revert, are there plans for a 4.0.1 release that this change will be in?