AttributeCore provides the lightest level of configurable attribute support. It is designed to be augmented on to a host class, and provides the host with the ability to configure attributes to store and retrieve state, but without support for attribute change events.
For example, attributes added to the host can be configured:
See the addAttr method, for the complete set of configuration options available for attributes.
Object/Classes based on AttributeCore can augment AttributeObservable
(with true for overwrite) and AttributeExtras to add attribute event and
additional, less commonly used attribute methods, such as modifyAttr, removeAttr and reset.
_addAttrscfgs
values
lazy
Implementation behind the public addAttrs method.
This method is invoked directly by get if it encounters a scenario in which an attribute's valueFn attempts to obtain the value an attribute in the same group of attributes, which has not yet been added (on demand initialization).
cfgs
Object
An object with attribute name/configuration pairs.
values
Object
An object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.
lazy
Boolean
Whether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.
_addLazyAttrname
[lazyCfg]
Finishes initializing an attribute which has been lazily added.
_addOutOfOrdername
cfg
Utility method used by get/set to add attributes encountered out of order when calling addAttrs().
For example, if:
this.addAttrs({
foo: {
setter: function() {
// make sure this bar is available when foo is added
this.get("bar");
}
},
bar: {
value: ...
}
});_getAttrname
Provides the common implementation for the public get method, allowing Attribute hosts to over-ride either method.
See get for argument details.
name
String
The name of the attribute.
The value of the attribute.
_getAttrInitValattr
cfg
initValues
Returns the initial value of the given attribute from either the default configuration provided, or the over-ridden value if it exists in the set of initValues provided and the attribute is not read-only.
The initial value of the attribute.
_getAttrsattrs
Implementation behind the public getAttrs method, to get multiple attribute values.
An object with attribute name/value pairs.
_getStateValname
[cfg]
Gets the stored value for the attribute, from either the internal state object, or the state proxy if it exits
The stored value of the attribute
_initAttrHostattrs
values
lazy
Constructor logic for attributes. Initializes the host state, and sets up the inital attributes passed to the constructor.
attrs
Object
The attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
values
Object
The initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.
lazy
Boolean
Whether or not to add attributes lazily (passed through to addAttrs).
_initAttrsattrs
values
lazy
Utility method to set up initial attributes defined during construction, either through the constructor.ATTRS property, or explicitly passed in.
attrs
Object
The attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
values
Object
The initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.
lazy
Boolean
Whether or not to add attributes lazily (passed through to addAttrs).
_isLazyAttrname
Checks whether or not the attribute is one which has been added lazily and still requires initialization.
name
String
The name of the attribute
true if it's a lazily added attribute, false otherwise.
_normAttrValsvalueHash
Utility method to normalize attribute values. The base implementation simply merges the hash to protect the original.
valueHash
Object
An object with attribute name/value pairs
An object literal with 2 properties - "simple" and "complex", containing simple and complex attribute values respectively keyed by the top level attribute name, or null, if valueHash is falsey.
_protectAttrsattrs
Utility method to protect an attribute configuration hash, by merging the entire object and the individual attr config objects.
attrs
Object
A hash of attribute to configuration object pairs.
A protected version of the attrs argument.
_setname
val
[opts]
Allows setting of readOnly/writeOnce attributes. See set for argument details.
A reference to the host object.
_setAttrname
value
[opts]
force
Provides the common implementation for the public set and protected _set methods.
See set for argument details.
A reference to the host object.
_setAttrsattrs
[opts]
Implementation behind the public setAttrs method, to set multiple attribute values.
A reference to the host object.
_setAttrValattrName
subAttrName
prevVal
newVal
[opts]
[attrCfg]
Updates the stored value of the attribute in the privately held State object, if validation and setter passes.
attrName
String
The attribute name.
subAttrName
String
The sub-attribute name, if setting a sub-attribute property ("x.y.z").
prevVal
Any
The currently stored value of the attribute.
newVal
Any
The value which is going to be stored.
[opts]
Object
optional
Optional data providing the circumstances for the change.
[attrCfg]
Object
optional
Optional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained the config from state.
true if the new attribute value was stored, false if not.
_setStateValname
value
Sets the stored value for the attribute, in either the internal state object, or the state proxy if it exits
name
String
The name of the attribute
value
Any
The value of the attribute
addAttrname
config
lazy
Adds an attribute with the provided configuration to the host object.
The config argument object supports the following properties:
A function, which will return the initial value to set on the attribute. This is useful for cases where the attribute configuration is defined statically, but needs to reference the host instance ("this") to obtain an initial value. If both the value and valueFn properties are defined, the value returned by the valueFn has precedence over the value property, unless it returns undefined, in which case the value property is used.
valueFn can also be set to a string, representing the name of the instance method to be used to retrieve the value.
The writeOnce attribute can also be set to the string "initOnly", in which case the attribute can only be set during initialization (when used with Base, this means it can only be set during construction)
The setter function used to massage or normalize the value passed to the set method for the attribute. The value returned by the setter will be the final stored value. Returning Attribute.INVALID_VALUE, from the setter will prevent the value from being stored.
setter can also be set to a string, representing the name of the instance method to be used as the setter function.
The getter function used to massage or normalize the value returned by the get method for the attribute. The value returned by the getter function is the value which will be returned to the user when they invoke get.
getter can also be set to a string, representing the name of the instance method to be used as the getter function.
The validator function invoked prior to setting the stored value. Returning false from the validator function will prevent the value from being stored.
validator can also be set to a string, representing the name of the instance method to be used as the validator function.
The setter, getter and validator are invoked with the value and name passed in as the first and second arguments, and with the context ("this") set to the host object.
Configuration properties outside of the list mentioned above are considered private properties used internally by attribute, and are not intended for public use.
name
String
The name of the attribute.
config
Object
An object with attribute configuration property/value pairs, specifying the configuration for the attribute.
NOTE: The configuration object is modified when adding an attribute, so if you need to protect the original values, you will need to merge the object.
lazy
Boolean
(optional) Whether or not to add this attribute lazily (on the first call to get/set).
A reference to the host object.
addAttrscfgs
values
lazy
Configures a group of attributes, and sets initial values.
NOTE: This method does not isolate the configuration object by merging/cloning. The caller is responsible for merging/cloning the configuration object if required.
cfgs
Object
An object with attribute name/configuration pairs.
values
Object
An object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.
lazy
Boolean
Whether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.
A reference to the host object.
attrAddedname
Checks if the given attribute has been added to the host
name
String
The name of the attribute to check.
true if an attribute with the given name has been added, false if it hasn't. This method will return true for lazily added attributes.
getname
Returns the current value of the attribute. If the attribute has been configured with a 'getter' function, this method will delegate to the 'getter' to obtain the value of the attribute.
name
String
The name of the attribute. If the value of the attribute is an Object,
dot notation can be used to obtain the value of a property of the object (e.g. get("x.y.z"))
The value of the attribute
getAttrsattrs
Gets multiple attribute values.
An object with attribute name/value pairs.
protectAttrsattrs
Utility method to protect an attribute configuration hash, by merging the entire object and the individual attr config objects.
attrs
Object
A hash of attribute to configuration object pairs.
A protected version of the attrs argument.
setname
value
[opts]
Sets the value of an attribute.
name
String
The name of the attribute. If the
current value of the attribute is an Object, dot notation can be used
to set the value of a property within the object (e.g. set("x.y.z", 5)).
value
Any
The value to set the attribute to.
[opts]
Object
optional
Optional data providing the circumstances for the change.
A reference to the host object.
_ATTR_CFGThe list of properties which can be configured for each attribute (e.g. setter, getter, writeOnce etc.).
This property is used internally as a whitelist for faster Y.mix operations.
INVALID_VALUEThe value to return from an attribute setter in order to prevent the set from going through.
You can return this value from your setter if you wish to combine validator and setter functionality into a single setter function, which either returns the massaged value to be stored or AttributeCore.INVALID_VALUE to prevent invalid values from being stored.