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JavaScript The JavaScript 'use strict' Statement

Posted by Vivekanand Rao
Vivekanand Rao
Courses Plus Student 20,884 Points

No Error in Chrome/Firefox Console for Duplicate named property in an object in strict mode.

Hi,

Even though I have duplicate keys in var badObject = {zoo: "animals", internet: "trolls", zoo: "keepers"}; I do not get this Uncaught SyntaxError: Duplicate data property in object literal not allowed in strict mode in Chrome 47.0.2526.73 (64-bit) & Firefox 42.0. However, I get an error when testing the same on Safari Version 8.0.8 (10600.8.9).

Why is that?

3 Answers

akak
akak
29,446 Points
akak
akak
29,446 Points

In ES6 duplicated object literal is allowed in strict mode. Chrome and Firefox implemented that part of specification, Safari not yet.

Here's an answer why it's allowed now: http://stackoverflow.com/a/30617831/5367597 Cheers!

Chyno Deluxe
Chyno Deluxe
16,936 Points
Chyno Deluxe
Chyno Deluxe
16,936 Points

I believe that the zoo key value gets replaced with keepers and ignores the initial animals value.

Vivekanand Rao
PLUS
Vivekanand Rao
Courses Plus Student 20,884 Points
Vivekanand Rao
Vivekanand Rao
Courses Plus Student 20,884 Points

Thanks akak.