Message
SyntaxError: missing : after property id
Error type
What went wrong?
When creating objects with the object initializer syntax, a colon (:) separates keys and values for the object's properties.
var obj = { propertyKey: 'value' };
Examples
Colons vs. equal signs
This code fails, as the equal sign can't be used this way in this object initializer syntax.
var obj = { propertyKey = 'value' };
// SyntaxError: missing : after property id
Correct would be to use a colon, or to use square brackets to assign a new property after the object has been created already.
var obj = { propertyKey: 'value' };
// or alternatively
var obj = { };
obj['propertyKey'] = 'value';
Empy properties
You can't create empty properties like this:
var obj = { propertyKey; };
// SyntaxError: missing : after property id
If you need to define a property without a value, you might use null as a value.
var obj = { propertyKey: null };
Computed properties
If you create a property key from an expression, you need to use square brackets. Otherwise the property name can't be computed:
var obj = { 'b'+'ar': 'foo' };
// SyntaxError: missing : after property id
Put the expression in brackets []:
var obj = { ['b'+'ar']: 'foo' };