[x3d-public] impact for JSON: ES6 and duplicate object literal properties

[yottzumm at gmail.com]

I can’t even find it in the ES5.1 standard.  Hmm.

John





On Dec 19, 2016 12:03 PM, "Don Brutzman" <brutzman at nps.edu> wrote:
Hmmm, maybe OK?  Here are some tests.
Maybe.   I'd like to put "use strict"; in front of it and run it through some browsers but I've been giving my hands a break. 

Codepen.io reports an error in chrome.



On 12/18/2016 6:01 AM, yottzumm at gmail.com wrote:
Note that in ES6, even in strict mode, the following will not cause an error:

var books = {
                title: “Understanding ECMAScript 6”,
                title: “JavaScript: The Good, the Bad and the Ugly”
};

However,

books.title === “JavaScript: The Good, the Bad and the Ugly”

Might you know the ES6 specification paragraph?

        http://www.ecma-international.org/ecma-262/6.0/#sec-terms-and-definitions-object
There are two mentions of “object literal” in standard and they appear unrelated.  It’s mentioned under “Duplicate Object Literal Properties” on page 75 of Understanding ECMAScript 6:

                “But in ECMAScript 6, the duplicate property check was removed. Strict and non-strict mode code no longer check for duplicate properties.”

I think maybe it’s just that the JSON parsers don’t catch it.

John

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