Why can't I add a Dog Face (u+1f436) field to my object without using a String? [duplicate]

Question

This:

var foo = {
 🐶 : true //Truely adorable
};

Gives me an Illegal Character error on Firefox and Chrome. However,

var foo = {
  '🐶' : true
};

Works perfectly. Why?
(You can also answer for a wider set of Unicode characters, but I really want to know more about Dog)

Here's a great explanation of what's allowed and what's not: mathiasbynens.be/notes/javascript-identifiers — CodingIntrigue
– CodingIntrigue, Commented Jun 23, 2015 at 14:02
Because its not in a unicode range of allowed identifier characters. The latter example is just a string containing the character. See What characters are valid for JavaScript variable names? — Alex K.
– Alex K., Commented Jun 23, 2015 at 14:03

Remy Lebeau · Accepted Answer · 2015-06-24 01:41:50Z

6

As the ECMAScript standard defines, valid identifiers must start with a Unicode code point with the Unicode property ID_Start.

You may use any of these code points as first character of your identifier:

Remy Lebeau

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answered Jun 23, 2015 at 14:11

Hauke P.

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2 Comments

Okay I found the Hiragana (ちえん) but it's still 3 characters so meh. Update: One character! In traditional chinese : 狗 (U+72D7).

Try an Egyptian hieroglyph. Not sure if your IDE (or even your browser) will render them though.