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JavaScript JavaScript Loops, Arrays and Objects Tracking Data Using Objects Using `for in` to Loop Through an Object's Properties

Irfan Hussain
PLUS
Irfan Hussain
Courses Plus Student 6,593 Points
Posted by Irfan Hussain
Irfan Hussain
Courses Plus Student 6,593 Points

You did not use var

In video Using for in to Loop through an Object's Properties you says that var and in is important in for loop.

But when you build for loop you use bellow syntax: for (prop in person)

Bit confused. I used var in my practice.

5 Answers

jeroenmaljers
jeroenmaljers
1,708 Points
jeroenmaljers
jeroenmaljers
1,708 Points

noticed the same: the exercise says :Bummer! It's a good idea to use the var keyword in a for in loop like this: for (var key in shanghai).: But Dave does not do that in the video.

Simon Coates
Simon Coates
28,694 Points
Simon Coates
Simon Coates
28,694 Points

take a look at this . I think there's scope implications.

louiecamacho
louiecamacho
10,980 Points
louiecamacho
louiecamacho
10,980 Points

YES, this makes it very confusing!

Steve Fan
Steve Fan
8,218 Points
Steve Fan
Steve Fan
8,218 Points

Yes, I have confused about that. Why he did not use "var" in "for in" but in the exercise, it requires to use "var" like a must.

xayide carassa
xayide carassa
3,195 Points
xayide carassa
xayide carassa
3,195 Points

very confused on this as well. Can any one from TreeHouse staff provide us with some clarity?

Simon Coates
Simon Coates
28,694 Points
Simon Coates
Simon Coates
28,694 Points

xayide carassa With an older forum post, you're unlikely to get attention from anyone on treehouse's staff unless they're already subscribed to that post, or you use the tagging syntax. Your start typing @ and then the person's name and a menu should come up to select the user (the menu is a little buggy sometimes). I think if they're still active, they should get notified.

so you can directly ask a member of staff or an advanced user (assuming they're active). Some of treehouse staff are pretty good at responding with detailed, thoughtful answers to user questions.