Question

var @foo = 'bar';
// SyntaxError: missing variable name.

{ '@foo' : 'bar' };
// SyntaxError: invalid label.

var obj = { '@foo' : 'bar' };
obj.@foo;
// TypeError: can't convert AttributeName to string

var obj = { '@foo' : 'bar' };
obj['@foo'];
// "bar"

Can anyone explain to me why the ‘@’ symbol is not allowed to be used in variable names and what I should be using it for?

Answer 1

It’s not reserved or special, it’s just not a valid javascript identifier character. For the same reason this works:

var obj = { 'foo-baz' : 'bar' };
obj['foo-baz'];

And this does not:

var obj = { 'foo-baz' : 'bar' };
obj.foo-baz;

Valid javascript identifiers must start with a letter or $, and may only contain letters, numbers, $, and _. Anything else in a property name will force you to use bracket notation.

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