GitHub
Twitterdefault
Returns the default value for instances of the defined type. The default value is defined on demand, when the property is read for the first time.
default()
A function can be provided that returns the default value used for this property, like:
{
prop: {
default: function() {
return [];
}
}
}
If the default value should be an object of some type, it should be specified as the return value of a function (the above call signature) so that all instances of this map don't point to the same object. For example, if the property value above had not returned an empty array but instead just specified an array using the next call signature below, all instances of that map would point to the same array (because JavaScript passes objects by reference).
Returns
{*}:
The default value. This will be passed through setter and type.
default
Any value can be provided as the default value used for this property, like:
{
prop: {
default: 'foo'
}
}
Parameters
- defaultVal
{*}:The default value, which will be passed through setter and type.
Use
The following defaults age to 0 and address to an object:
// A default age of `0`:
const Person = DefineMap.extend( {
age: {
default: 0
},
address: {
default: function() {
return { city: "Chicago", state: "IL" };
}
}
} );
Alternates
There is a third way to provide a default value, which is explained in the Default docs page. default lowercased is for providing default values for a property type, while Default uppercased is for providing a constructor function, which will be invoked with new to create a default value for each instance of this map.