JavaScript: Undefined property when looping through array

Asked Mar 04 '16 at 11:04

Active Mar 04 '16 at 11:05

Viewed 69 times

I have the following array, and am trying to loop through it.

var Periods = [
            { Label: "13:00", Open: true },
            { Label: "14:00", Open: true },
            { Label: "15:00", Open: true },
            { Label: "16:00", Open: false},
            { Label: "17:00", Open: true },
            { Label: "18:00", Open: true },
            { Label: "19:00", Open: true },
            { Label: "20:00", Open: true },
            { Label: "21:00", Open: false},
            { Label: "22:00", Open: true }];

for (period in Periods) {
    alert(period.Label);
}

Running this, loops once for each object, but gives me 'Undefined' values.

I have absolutely no knowledge of JavaScript, and it might be that I am not searching for the right solution, so apologies if this is a double post. Seems like such a trivial thing to do.

EDIT: I am using a Knockout-like library, so would prefer not to change the style in which the array is defined.

edited Mar 04 '16 at 11:05

asked Mar 04 '16 at 11:04

Wessel du Plooy

2

you should use Periods[period].Label – Daniel Mar 04 '16 at 11:05
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in – Nina Scholz Mar 04 '16 at 11:06
also use `if(Periods.hasOwnProperty(period))` before alert – xkeshav Mar 04 '16 at 11:06
1

for (period in Periods) { console.log(Periods[period].Label); } – Raja Sekar Mar 04 '16 at 11:07
2

`period`is an index not an object. – ADreNaLiNe-DJ Mar 04 '16 at 11:07
People, **don't use `for..in` at all to loop through arrays.** Spare yourselves the suggestions about `hasOwnProperty` and such. – deceze Mar 04 '16 at 11:09

JavaScript: Undefined property when looping through array

0 Answers0