Typescript: Uncaught typeError, Cannot read property “push” of undefined











up vote
1
down vote

favorite












private readonly lives: number = 5;   

public loadLifeImages() {
var ammount: Array<any>;
for (var i = 0; i < this.lives; i++) {
ammount.push(i);
}
ammount.forEach((v, i) => {
console.log(this.lives);
console.log(i);
var newLifeImage = new Image();
newLifeImage.src = './assets/images/SpaceShooterRedux/PNG/UI/PlayerLife1_blue.png';
newLifeImage.onload = () => {
this.ctx.drawImage(newLifeImage, i * 50, 50, 30, 30);
}
})
}


I'm trying to push these numbers to this array in Typescript, so I can use a for each loop to put the images on my canvas, however it gives the error 'cannot read property "push" of undefined' I know it's a bit double, but I really can't figure out any other way to do it. Can someone figure out what it is? thanks in advance!










share|improve this question


























    up vote
    1
    down vote

    favorite












    private readonly lives: number = 5;   

    public loadLifeImages() {
    var ammount: Array<any>;
    for (var i = 0; i < this.lives; i++) {
    ammount.push(i);
    }
    ammount.forEach((v, i) => {
    console.log(this.lives);
    console.log(i);
    var newLifeImage = new Image();
    newLifeImage.src = './assets/images/SpaceShooterRedux/PNG/UI/PlayerLife1_blue.png';
    newLifeImage.onload = () => {
    this.ctx.drawImage(newLifeImage, i * 50, 50, 30, 30);
    }
    })
    }


    I'm trying to push these numbers to this array in Typescript, so I can use a for each loop to put the images on my canvas, however it gives the error 'cannot read property "push" of undefined' I know it's a bit double, but I really can't figure out any other way to do it. Can someone figure out what it is? thanks in advance!










    share|improve this question
























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      private readonly lives: number = 5;   

      public loadLifeImages() {
      var ammount: Array<any>;
      for (var i = 0; i < this.lives; i++) {
      ammount.push(i);
      }
      ammount.forEach((v, i) => {
      console.log(this.lives);
      console.log(i);
      var newLifeImage = new Image();
      newLifeImage.src = './assets/images/SpaceShooterRedux/PNG/UI/PlayerLife1_blue.png';
      newLifeImage.onload = () => {
      this.ctx.drawImage(newLifeImage, i * 50, 50, 30, 30);
      }
      })
      }


      I'm trying to push these numbers to this array in Typescript, so I can use a for each loop to put the images on my canvas, however it gives the error 'cannot read property "push" of undefined' I know it's a bit double, but I really can't figure out any other way to do it. Can someone figure out what it is? thanks in advance!










      share|improve this question













      private readonly lives: number = 5;   

      public loadLifeImages() {
      var ammount: Array<any>;
      for (var i = 0; i < this.lives; i++) {
      ammount.push(i);
      }
      ammount.forEach((v, i) => {
      console.log(this.lives);
      console.log(i);
      var newLifeImage = new Image();
      newLifeImage.src = './assets/images/SpaceShooterRedux/PNG/UI/PlayerLife1_blue.png';
      newLifeImage.onload = () => {
      this.ctx.drawImage(newLifeImage, i * 50, 50, 30, 30);
      }
      })
      }


      I'm trying to push these numbers to this array in Typescript, so I can use a for each loop to put the images on my canvas, however it gives the error 'cannot read property "push" of undefined' I know it's a bit double, but I really can't figure out any other way to do it. Can someone figure out what it is? thanks in advance!







      arrays typescript undefined push






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 13 at 14:04









      J Peene

      112




      112
























          1 Answer
          1






          active

          oldest

          votes

















          up vote
          1
          down vote



          accepted










          This can be fixed by initializing ammount like this:



          var ammount: Array<any> = ;


          This is because just typing var ammount: Array<any> doesn't give a value to ammount, so it becomes undefined (the default value for all javascript variables). = initializes the variable to be an empty array.



          However, I want to point out that judging from the code you have here, there is no good reason to create a new array and just push the values into it. Instead, you could just put the forEach logic inside the for-loop.






          share|improve this answer























            Your Answer






            StackExchange.ifUsing("editor", function () {
            StackExchange.using("externalEditor", function () {
            StackExchange.using("snippets", function () {
            StackExchange.snippets.init();
            });
            });
            }, "code-snippets");

            StackExchange.ready(function() {
            var channelOptions = {
            tags: "".split(" "),
            id: "1"
            };
            initTagRenderer("".split(" "), "".split(" "), channelOptions);

            StackExchange.using("externalEditor", function() {
            // Have to fire editor after snippets, if snippets enabled
            if (StackExchange.settings.snippets.snippetsEnabled) {
            StackExchange.using("snippets", function() {
            createEditor();
            });
            }
            else {
            createEditor();
            }
            });

            function createEditor() {
            StackExchange.prepareEditor({
            heartbeatType: 'answer',
            convertImagesToLinks: true,
            noModals: true,
            showLowRepImageUploadWarning: true,
            reputationToPostImages: 10,
            bindNavPrevention: true,
            postfix: "",
            imageUploader: {
            brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
            contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
            allowUrls: true
            },
            onDemand: true,
            discardSelector: ".discard-answer"
            ,immediatelyShowMarkdownHelp:true
            });


            }
            });














            draft saved

            draft discarded


















            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53282766%2ftypescript-uncaught-typeerror-cannot-read-property-push-of-undefined%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown

























            1 Answer
            1






            active

            oldest

            votes








            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes








            up vote
            1
            down vote



            accepted










            This can be fixed by initializing ammount like this:



            var ammount: Array<any> = ;


            This is because just typing var ammount: Array<any> doesn't give a value to ammount, so it becomes undefined (the default value for all javascript variables). = initializes the variable to be an empty array.



            However, I want to point out that judging from the code you have here, there is no good reason to create a new array and just push the values into it. Instead, you could just put the forEach logic inside the for-loop.






            share|improve this answer



























              up vote
              1
              down vote



              accepted










              This can be fixed by initializing ammount like this:



              var ammount: Array<any> = ;


              This is because just typing var ammount: Array<any> doesn't give a value to ammount, so it becomes undefined (the default value for all javascript variables). = initializes the variable to be an empty array.



              However, I want to point out that judging from the code you have here, there is no good reason to create a new array and just push the values into it. Instead, you could just put the forEach logic inside the for-loop.






              share|improve this answer

























                up vote
                1
                down vote



                accepted







                up vote
                1
                down vote



                accepted






                This can be fixed by initializing ammount like this:



                var ammount: Array<any> = ;


                This is because just typing var ammount: Array<any> doesn't give a value to ammount, so it becomes undefined (the default value for all javascript variables). = initializes the variable to be an empty array.



                However, I want to point out that judging from the code you have here, there is no good reason to create a new array and just push the values into it. Instead, you could just put the forEach logic inside the for-loop.






                share|improve this answer














                This can be fixed by initializing ammount like this:



                var ammount: Array<any> = ;


                This is because just typing var ammount: Array<any> doesn't give a value to ammount, so it becomes undefined (the default value for all javascript variables). = initializes the variable to be an empty array.



                However, I want to point out that judging from the code you have here, there is no good reason to create a new array and just push the values into it. Instead, you could just put the forEach logic inside the for-loop.







                share|improve this answer














                share|improve this answer



                share|improve this answer








                edited Nov 13 at 14:21

























                answered Nov 13 at 14:14









                ShamPooSham

                462313




                462313






























                    draft saved

                    draft discarded




















































                    Thanks for contributing an answer to Stack Overflow!


                    • Please be sure to answer the question. Provide details and share your research!

                    But avoid



                    • Asking for help, clarification, or responding to other answers.

                    • Making statements based on opinion; back them up with references or personal experience.


                    To learn more, see our tips on writing great answers.





                    Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


                    Please pay close attention to the following guidance:


                    • Please be sure to answer the question. Provide details and share your research!

                    But avoid



                    • Asking for help, clarification, or responding to other answers.

                    • Making statements based on opinion; back them up with references or personal experience.


                    To learn more, see our tips on writing great answers.




                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53282766%2ftypescript-uncaught-typeerror-cannot-read-property-push-of-undefined%23new-answer', 'question_page');
                    }
                    );

                    Post as a guest















                    Required, but never shown





















































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown

































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown







                    Popular posts from this blog

                    How to change which sound is reproduced for terminal bell?

                    Can I use Tabulator js library in my java Spring + Thymeleaf project?

                    Title Spacing in Bjornstrup Chapter, Removing Chapter Number From Contents