SyntaxError: missing : after property id
The JavaScript exception "missing : after property id" occurs when objects are created
using the object initializer syntax.
A colon (:
) separates keys and values for the
object's properties. Somehow, this colon is missing or misplaced.
Message
SyntaxError: Expected ':' (Edge)
SyntaxError: missing : after property id (Firefox)
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';
Empty 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' };