CODEWITHSUNDEEP
javascriptangulartypescript
BeepBopImaRobot
BeepBopImaRobot

Reputation: 113

Array not emptying

Im trying to empty the array below but it it just keeps piling onto it instead of actually emptying it. Any ideas why this happens?

displaytaken[];

Edit: Adding a StackBlits:

Im getting way to confused. With the Snippet/JQ and im changing to much to get a accurate answer out of this.

Issue now is that it actually works in the stackblitz so something els is asstray will be editing it to reach a working recreation

https://stackblitz.com/edit/angular-ivy-kdec3f?

Another Edit: Im finding it hard to recreate the issue but on the stacklits youll notice a function called checkinbetween() in there is a array called : filteredArray This is storing data even if i clear it despite changing it from const to var so its duplicating all outputs on my side

Screenshot to help show whats happening on my side:

enter image description here

enter image description here

enter image description here

As u can see I clear the array but then when I add to it again the old values are there still

Upvotes: 1

Views: 86

Answers (1)

Titulum
Titulum

Reputation: 11466

You are using Typescript, which gives you the added advantages of using types. Also, I would advice you to start using immutablility.

Instead of populating some 'global' array, you should create functions for you that return you the data that you need:

// Instead of this
const myDateArray: Date[] = [];
for (const someValue of someOtherDateArray) {
  if (some.condition()) {
    myDateArray.push(someValue);
  }
}

// Do this:
function getDateArray(otherDateArray: Date[]): Date[] {
  return otherDateArray.filter(date => some.condition());
}

That way, you don't need to clear the date array, as a new one can be requested on the fly.

To get to your answer, I assume you are looping over a lot of date arrays, and displaying them as taken dates in an alert box. here is how you can do that without clearing the array everytime:

const allTakenDates = [
     [
        new Date('2018-01-16'),
        new Date('2018-03-26'),
        new Date('2018-05-22'),
        new Date('2018-12-01'),
        new Date('2018-01-23'),
    ],
     [
        new Date('2019-01-16'),
        new Date('2019-03-26'),
        new Date('2019-05-22'),
        new Date('2019-12-01'),
        new Date('2019-01-23'),
    ],
     [
        new Date('2020-01-16'),
        new Date('2020-03-26'),
        new Date('2020-05-22'),
        new Date('2020-12-01'),
        new Date('2020-01-23'),
    ]
];

function getDatesAsString(dates: Date[]): string[] {
    return dates.map(date => `${date.getFullYear()}/${date.getMonth() + 1}/${date.getDate()}`);
}

for (const dates of allTakenDates) {
    
    const formattedDates = getDatesAsString(dates).join();
    alert('The following dates are taken: ' + formattedDates);
}

And here is a working example of that code.

Upvotes: 2

Related Questions