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











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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!










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    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






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      asked Nov 13 at 14:04









      J Peene

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      112
























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          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























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            1 Answer
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            active

            oldest

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            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






























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