Dash on the end of javascript object property

Question

can i use dash on the end of javascript object property name like this. I could not find in any documentation that this is not valid but i got some strange results when trying to access value myProp- in this case.

var myObject = {"myProp-":"myValue"};

i can only access to this value like this myObject["myProp-"] and i would like to access like

myObject.myProp-

but i got " SyntaxError: Unexpected token } "

Yes you can, but in this case you have to access it like this: `myObject["myProp-"]`. There are a lot of [info](https://www.google.by/search?q=javascript+object+valid+keys&aq=1&oq=javascript+object+vali&aqs=chrome.2.57j0l3j62l2.10197j0&sourceid=chrome&ie=UTF-8#hl=en&sclient=psy-ab&q=javascript+object+valid+keys&oq=javascript+object+valid+keys&gs_l=serp.12...0.0.0.152521.0.0.0.0.0.0.0.0..0.0...0.0...1c..8.psy-ab.0szo_YiWUGs&pbx=1&bav=on.2,or.r_qf.&bvm=bv.44770516,d.Yms&fp=94aab36a3e6c7776&biw=1280&bih=923).. — dfsq, Apr 04 '13 at 15:19
More info on variable names validity : http://stackoverflow.com/questions/1661197/valid-characters-for-javascript-variable-names — Laurent S., Apr 04 '13 at 15:19
I don't think anything with a dash is a valid variable name becaue JS thinks it's a minus sign 1-2 (one minus two). You can use it as part of a string when surrounded by quotes and then use that string as an identifier but that's the only way you can use it. — HMR, Apr 04 '13 at 15:24

score 5 · Accepted Answer · answered Apr 04 '13 at 15:21

5

You'll have to use bracket notation instead of dot notation:

myObject["myProp-"]

answered Apr 04 '13 at 15:21

chrx

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Just saw [this.](https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Working_with_Objects) – user12733 Apr 04 '13 at 15:32
@chrx Have you any idea briefly why we need to use square bracket instead of we already define in '{' ? – VjyV Nov 25 '16 at 10:04

score 1 · Answer 2 · answered Apr 04 '13 at 15:21

var myObject = {"myProp-":"myValue", "foo": "bar" };

myObject.foo;
myObject["foo"]; // these are equivalent

myObject.myProp-; // syntax error
myObject["myProp-"]; // this is fine

var key = "myProp-";
myObject[key]; // this works as well (dynamic index)
myObject.key; // undefined

Bracket notation are dot notation are equivalent.

Dash on the end of javascript object property

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