Add an Empty Array to An Array with Existing Values?

Question

I'm currently receiving this error with the following code:

TypeError: data.data.trek.days[current_day] is undefined

The problem I am having is that I need to add the current_day along with an empty places array to the existing array structure if one hasn't been previously provided. How can I do this?

data.data.trek.days[current_day].places.push({
    "url": url,
    "img_src": img_src,
    "title": title,
    "time_going_hour": time_going_hour,
    "time_going_minutes": time_going_minutes,
    "duration": "3600",
    "id": id,
    "type": type,
    "city_id": city_id
});

You're trying to see if data.data.trek.days[current_day].places has length? — Ohgodwhy
– Ohgodwhy, Commented May 21, 2013 at 19:30
UPDATE: When I try to do: data.data.trek.days.push(current_day); I get this error: TypeError: data.data.trek.days.push is not a function — Jason Biondo
– Jason Biondo, Commented May 21, 2013 at 19:30
is days even defined? print out via console.log(data.data.trek) and see if days exist as a member — dchhetri
– dchhetri, Commented May 21, 2013 at 19:31
No, I want to add the current_day as a key in the days array and add an empty places array as a value of that key. — Jason Biondo
– Jason Biondo, Commented May 21, 2013 at 19:31
Yes, days is defined and returns: 1 Object { places=[3]} 2 Object { places=[4]} — Jason Biondo
– Jason Biondo, Commented May 21, 2013 at 19:32

dchhetri · Accepted Answer · 2013-05-21 19:33:37Z

1

From your comment you seem to want this:

data.data.trek.days = data.data.trek.days || {};
data.data.trek.days[current_day] = data.data.trek.days[current_day] || {};
data.data.trek.days[current_day].places = data.data.trek.days[current_day].places || [];
data.data.trek.days[current_day].places.push({ ... });

answered May 21, 2013 at 19:33

dchhetri

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