Problem of Restricting Array to Single Element at Once

Question

Problem of Restricting Array to Single Element at Once

I seem to be facing an issue with a seemingly straightforward function that creates an array - and I'm unable to pinpoint the root cause of the problem. It's probably something simple, but for some reason, it eludes me.

Here is the function in question:

private onSelection(selection)
{
    if (selection)
    {
        const selectionsArray = [];
        selectionsArray.push(selection);
        console.log(selectionsArray);
        console.log(selectionsArray.length);
        return selectionsArray;
    }
}

The "selection" is passed through a checkbox, like this:

<md-checkbox (click)="onSelection('A')">A</md-checkbox>
<md-checkbox (click)="onSelection('B')">B</md-checkbox>
<md-checkbox (click)="onSelection('C')">C</md-checkbox>

Currently, irrespective of which checkboxes are clicked, my array only contains one item at all times, as evident from the length being constantly 1 when logged to the console. What could I possibly be overlooking here? Why isn't the array expanding to accommodate multiple selections being added?

javascript arrays typescript

Answer 1

Answer №1

When handling your onSelection, it is important to note that the existing array gets reset each time before adding a selected element. To prevent this from happening, it is advisable to initialize your array outside of the onSelection function.

Here is a suggestion: You might consider eliminating the if (selection) condition in your code as it will always be true. Instead, check if the selected element already exists in your selectionsArray before adding it. This way, you can avoid any duplicate entries in your selectionsArray. Additionally, you should remove the const declaration for your selectionsArray since it serves no meaningful purpose.

const selectionsArray = [];
private onSelection(selection)
{
  if (selection)
  {
    selectionsArray.push(selection);
    console.log(selectionsArray);
    console.log(selectionsArray.length);
    return selectionsArray;
  }
}

Answer 2

When handling your onSelection, it is important to note that the existing array gets reset each time before adding a selected element. To prevent this from happening, it is advisable to initialize your array outside of the onSelection function.

Here is a suggestion: You might consider eliminating the if (selection) condition in your code as it will always be true. Instead, check if the selected element already exists in your selectionsArray before adding it. This way, you can avoid any duplicate entries in your selectionsArray. Additionally, you should remove the const declaration for your selectionsArray since it serves no meaningful purpose.

const selectionsArray = [];
private onSelection(selection)
{
  if (selection)
  {
    selectionsArray.push(selection);
    console.log(selectionsArray);
    console.log(selectionsArray.length);
    return selectionsArray;
  }
}

Problem of Restricting Array to Single Element at Once

Answer №1

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