What could be the reason for Angular to merge the element at index 0 of an array into a subarray instead of doing

Question

What could be the reason for Angular to merge the element at index 0 of an array into a subarray instead of doing

After setting up the Array in my oninit function, I encountered an issue where one part of the array was functioning as intended while the other returned an error.

 this.tests = [{
      status: 0,
      testresults: [{       
        name: 'test',
          id: 1
      }]
    }
    ]
    ;

    this.tests.push([{
      status: 1,
      testresults: [{       
        name: 'test2',
          id: 2
      }]
    }
    ]
    }]);

To achieve my goal of pushing query results into the testresults array inside tests, I used the following code:

  this.tests[0].testresults.push(this.qryresults);
  this.tests[1].testresults.push(this.qryresults);

Although Index 0 worked correctly, Index 1 resulted in the following error message being displayed:

"ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'push' of undefined
TypeError: Cannot read property 'push' of undefined"

javascript arrays angular typescript

Answer 1

Answer №1

On the second iteration, you are mistakenly pushing an array instead of an object, leading to an error due to the absence of the testresults property in the pushed array. Below is a revised code snippet that demonstrates the correct approach:

(function() {
  this.qryresults = "some test data"
  this.tests = [{
    status: 0,
    testresults: [
      { name: 'test', id: 1 }
    ]
  }];

  this.tests.push({ 
    status: 1,
    testresults: [
      { name: 'test2', id: 2 }
    ]
  });              

  this.tests[0].testresults.push(this.qryresults);
  this.tests[1].testresults.push(this.qryresults);
  console.log(this.tests)
})()

Answer 2

On the second iteration, you are mistakenly pushing an array instead of an object, leading to an error due to the absence of the testresults property in the pushed array. Below is a revised code snippet that demonstrates the correct approach:

(function() {
  this.qryresults = "some test data"
  this.tests = [{
    status: 0,
    testresults: [
      { name: 'test', id: 1 }
    ]
  }];

  this.tests.push({ 
    status: 1,
    testresults: [
      { name: 'test2', id: 2 }
    ]
  });              

  this.tests[0].testresults.push(this.qryresults);
  this.tests[1].testresults.push(this.qryresults);
  console.log(this.tests)
})()

Answer 3

Answer №2

The act of pushing an array into another array can be achieved by adding an object to the array in the following manner:

this.array.push({
  type: 'fruit',
  items: [{
    name: 'apple',
    id: 1
  }]

});

Answer 4

The act of pushing an array into another array can be achieved by adding an object to the array in the following manner:

this.array.push({
  type: 'fruit',
  items: [{
    name: 'apple',
    id: 1
  }]

});

Answer 5

Answer №3

Sure, to resolve this problem, use the code snippet below:

data = [{
    status: 0,
    results: [{
        name: 'result',
        id: 1
    }]
}];

queryResults = [{
    status: 1,
    results: [{
        name: 'result2',
        id: 2
    }]
}]

data.push(...queryResults);

Answer 6

Sure, to resolve this problem, use the code snippet below:

data = [{
    status: 0,
    results: [{
        name: 'result',
        id: 1
    }]
}];

queryResults = [{
    status: 1,
    results: [{
        name: 'result2',
        id: 2
    }]
}]

data.push(...queryResults);

What could be the reason for Angular to merge the element at index 0 of an array into a subarray instead of doing

Answer №1

Answer №2

Answer №3

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