Why is this is undefined when mocking event in React unit testing, using sinon.spy to mock function and enzyme.shallow render for React Component?










1















Whenever I try to simulate an event where I am passing the event object, I am getting that this is undefined.



const onBlur = sinon.spy(Input.prototype.handleBlur);
const wrapper = shallow(<Input handleBlur=onBlur />);
//...
wrapper.find('input').simulate('blur', target: value: '' );


Inside of the handleBlur method, this is undefined. However, if I decide not to mock the event object, then event is undefined.



Also, I tried using mount instead:

const wrapper = shallow(<Input handleBlur=onBlur />);

But, it's the same thing. However, I couldn't even get to that point until I updated the npm libraries.










share|improve this question




























    1















    Whenever I try to simulate an event where I am passing the event object, I am getting that this is undefined.



    const onBlur = sinon.spy(Input.prototype.handleBlur);
    const wrapper = shallow(<Input handleBlur=onBlur />);
    //...
    wrapper.find('input').simulate('blur', target: value: '' );


    Inside of the handleBlur method, this is undefined. However, if I decide not to mock the event object, then event is undefined.



    Also, I tried using mount instead:

    const wrapper = shallow(<Input handleBlur=onBlur />);

    But, it's the same thing. However, I couldn't even get to that point until I updated the npm libraries.










    share|improve this question


























      1












      1








      1








      Whenever I try to simulate an event where I am passing the event object, I am getting that this is undefined.



      const onBlur = sinon.spy(Input.prototype.handleBlur);
      const wrapper = shallow(<Input handleBlur=onBlur />);
      //...
      wrapper.find('input').simulate('blur', target: value: '' );


      Inside of the handleBlur method, this is undefined. However, if I decide not to mock the event object, then event is undefined.



      Also, I tried using mount instead:

      const wrapper = shallow(<Input handleBlur=onBlur />);

      But, it's the same thing. However, I couldn't even get to that point until I updated the npm libraries.










      share|improve this question
















      Whenever I try to simulate an event where I am passing the event object, I am getting that this is undefined.



      const onBlur = sinon.spy(Input.prototype.handleBlur);
      const wrapper = shallow(<Input handleBlur=onBlur />);
      //...
      wrapper.find('input').simulate('blur', target: value: '' );


      Inside of the handleBlur method, this is undefined. However, if I decide not to mock the event object, then event is undefined.



      Also, I tried using mount instead:

      const wrapper = shallow(<Input handleBlur=onBlur />);

      But, it's the same thing. However, I couldn't even get to that point until I updated the npm libraries.







      javascript reactjs unit-testing sinon enzyme






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      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 14 '18 at 16:48







      Michael M. Adkins

















      asked Nov 13 '18 at 21:26









      Michael M. AdkinsMichael M. Adkins

      112110




      112110






















          1 Answer
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          0














          try using



          const onBlur = sinon.spy(Input.prototype, "handleBlur");


          instead



          const onBlur = sinon.spy(Input.prototype.handleBlur);





          share|improve this answer























          • I tried that. It's the same problem either way.

            – Michael M. Adkins
            Nov 14 '18 at 16:47










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          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          try using



          const onBlur = sinon.spy(Input.prototype, "handleBlur");


          instead



          const onBlur = sinon.spy(Input.prototype.handleBlur);





          share|improve this answer























          • I tried that. It's the same problem either way.

            – Michael M. Adkins
            Nov 14 '18 at 16:47















          0














          try using



          const onBlur = sinon.spy(Input.prototype, "handleBlur");


          instead



          const onBlur = sinon.spy(Input.prototype.handleBlur);





          share|improve this answer























          • I tried that. It's the same problem either way.

            – Michael M. Adkins
            Nov 14 '18 at 16:47













          0












          0








          0







          try using



          const onBlur = sinon.spy(Input.prototype, "handleBlur");


          instead



          const onBlur = sinon.spy(Input.prototype.handleBlur);





          share|improve this answer













          try using



          const onBlur = sinon.spy(Input.prototype, "handleBlur");


          instead



          const onBlur = sinon.spy(Input.prototype.handleBlur);






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 13 '18 at 22:56









          user1705722user1705722

          91




          91












          • I tried that. It's the same problem either way.

            – Michael M. Adkins
            Nov 14 '18 at 16:47

















          • I tried that. It's the same problem either way.

            – Michael M. Adkins
            Nov 14 '18 at 16:47
















          I tried that. It's the same problem either way.

          – Michael M. Adkins
          Nov 14 '18 at 16:47





          I tried that. It's the same problem either way.

          – Michael M. Adkins
          Nov 14 '18 at 16:47



















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