Javascript Object Property Naming

Question

I'm currently learning javascript from the following book 'JavaScript: The Good Parts - O'Reilly Media', which says the following:

The quotes around a property’s name in an object literal are optional if the name would be a legal JavaScript name and not a reserved word. So quotes are required around"first-name", but are optional around first_name.

Question: From my research 'first-name' is not a keyword in javascript, so why does the author say quotes are required around it?

To rephrase the book: the quotes are required if the name is not a legal JavaScript name or if the name is a reserved word. — Ted Hopp
– Ted Hopp, Commented Jul 28, 2013 at 19:16

Denys Séguret · Accepted Answer · 2013-07-28 19:15:14Z

3

That's because first-name isn't a valid identifier name as defined by ECMAScript :

enter image description here

answered Jul 28, 2013 at 19:15

Denys Séguret

384k90 gold badges813 silver badges780 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

ericjbasti · Accepted Answer · 2013-07-28 19:44:28Z

0

JavaScript is going to see that as var first minus var name.

It's not first-name thats illegal, it's the us of -.

edited Jul 28, 2013 at 19:44

user1907906

answered Jul 28, 2013 at 19:16

ericjbasti

2,08517 silver badges19 bronze badges

Collectives™ on Stack Overflow

Javascript Object Property Naming

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related