Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript

Posted by melissamyra
.a{fill-rule:evenodd;}techdegree seal-36
melissamyra
Front End Web Development Techdegree Graduate 18,858 Points

can 'var' be 'let' or 'const' in a for in loop?

Sample code :

for (var key in person) {
 console.log(`${key} : ${person[key]}`);
}

1 Answer

Steven Parker
Steven Parker
231,153 Points
Steven Parker
Steven Parker
231,153 Points

It's actually quite advantageous to use "let" in some situations because the variable scope will be limited to within the loop body.

You wouldn't use "const" since you will want the value to change as the loop runs.

melissamyra
.a{fill-rule:evenodd;}techdegree seal-36
melissamyra
Front End Web Development Techdegree Graduate 18,858 Points

Thank you Steven! I was confused about variables being a parameter in the 'for in' loop or if 'var' was part of the loop syntax, but I see now how it works the same as other loops like the index 'i' thing.