How to correctly get length of array

Question

I'm having a bit of a problem so i have an array with objects when i log it it displays everything fine but when i try the .length function it returns 0 for some reason.

Here's my code:

async getTicketType(updatedTicketType) {
    await this.getTicketTypes();
    if (this.typeOptions) {
        console.log('ik kom hier');
        console.log(this.typeOptions);
        console.log(this.typeOptions.length);
        for (let i = 0; i < this.typeOptions.length; i++) {
            console.log('ik kom hier');
            if (this.typeOptions[i]["value"] === updatedTicketType) {
                this.currentTypeOptions = this.typeOptions[i];
            }
        }
    }
}

And here's a picture of the logs:

And here's a picture of the logs

Try reading [this](https://stackoverflow.com/q/52873516/9787887) — Loi Nguyen Huynh, Dec 23 '19 at 13:56

score 0 · Answer 1 · answered Dec 23 '19 at 13:42

0

This is because your array has 10 undefined values therefore it does not actually have a length property, if you make sure that there is some value in each element then you will be able to get the array. It's a feature of JS and how the length property on the array is computed.

answered Dec 23 '19 at 13:42

Michael

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The values are filled. the this.getTicketTypes fills this.typeOptions through an api call – kevin van gils Dec 23 '19 at 13:45
What does the data look like? are you sure that it actually came? – Michael Dec 23 '19 at 14:01
Yeah every iteration has a label and a value which are filled label is filled with a String and Value with an integer – kevin van gils Dec 23 '19 at 14:08
please share you api code so we can get a better sense of the data you are referring to – Michael Dec 23 '19 at 14:16

score 0 · Answer 2 · answered Dec 23 '19 at 13:48

0

You can try to parse it to an array again:

// arr is an array with contains 10 items
var arr = JSON.parse(JSON.stringify(this.typeOptions));

Then, continuing with the loop...

answered Dec 23 '19 at 13:48

Tân

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How to correctly get length of array

2 Answers2