The BaseCore class, is the lightest version of Base, and provides Base's basic lifecycle management and ATTRS construction support, but doesn't fire init/destroy or attribute change events.
BaseCore also handles the chaining of initializer and destructor methods across the hierarchy as part of object construction and destruction. Additionally, attributes configured through the static ATTRS property for each class in the hierarchy will be initialized by BaseCore.
Classes which require attribute support, but don't intend to use/expose attribute change events can extend BaseCore instead of Base for optimal kweight and runtime performance.
3.11.0 BACK COMPAT NOTE FOR COMPONENT DEVELOPERS
Prior to version 3.11.0, ATTRS would get added a class at a time. That is:
for each (class in the hierarchy) {
Call the class Extension constructors.
Add the class ATTRS.
Call the class initializer
Call the class Extension initializers.
}
As of 3.11.0, ATTRS from all classes in the hierarchy are added in one addAttrs call
before any initializers are called. That is, the flow becomes:
for each (class in the hierarchy) {
Call the class Extension constructors.
}
Add ATTRS for all classes
for each (class in the hierarchy) {
Call the class initializer.
Call the class Extension initializers.
}
Adding all ATTRS at once fixes subtle edge-case issues with subclass ATTRS overriding
superclass setter, getter or valueFn definitions and being unable to get/set attributes
defined by the subclass. It also leaves us with a cleaner order of operation flow moving
forward.
However, it may require component developers to upgrade their components, for the following scenarios:
setter, getter or valueFn code which
expects a superclass' initializer to have run.This is expected to be rare, but to support it, Base now supports a _preAddAttrs(), method
hook (same signature as addAttrs). Components can implement this method on their prototype
for edge cases which do require finer control over the order in which attributes are added
(see widget-htmlparser for example).
initializersOlder extensions, which were written before initializer support was added, had a lot of
initialization code in their constructors. For example, code which acccessed superclass
attributes. With the new flow this code would not be able to see attributes. The recommendation
is to move this initialization code to an initializer on the Extension, which was the
recommendation for anything created after initializer support for Extensions was added.
BaseCorecfg
cfg
Object
Object with configuration property name/value pairs. The object can be used to provide initial values for the objects published attributes.
_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: ...
}
});_aggregateAttrsallAttrs
A helper method, used by _initHierarchyData to aggregate attribute configuration across the instances class hierarchy.
The method will protect the attribute configuration value to protect the statically defined default value in ATTRS if required (if the value is an object literal, array or the attribute configuration has cloneDefaultValue set to shallow or deep).
allAttrs
Array
An array of ATTRS definitions across classes in the hierarchy (subclass first, Base last)
The aggregate set of ATTRS definitions for the instance
_attrCfgHashUtility method to define the attribute hash used to filter/whitelist property mixes for this class for iteration performance reasons.
_baseDestroyInternal destroy implementation for BaseCore
_baseInitInternal initialization implementation for BaseCore
_cloneDefaultValuecfg
This method assumes that the value has already been checked to be an object. Since it's on a critical path, we don't want to re-do the check.
cfg
Object
_destroyHierarchyDestroys the class hierarchy for this instance by invoking the destructor method on the prototype of each class in the hierarchy.
_filterAdHocAttrsallAttrs
userVals
allAttrs
Object
The set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.
userVals
Object
The config object passed in by the user, from which adhoc attrs are to be filtered.
The set of adhoc attributes passed in, in the form of an object with attribute name/configuration pairs.
_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.
_getAttrCfgsReturns an aggregated set of attribute configurations, by traversing the class hierarchy.
The hash of attribute configurations, aggregated across classes in the hierarchy This value is cached the first time the method, or _getClasses, is invoked. Subsequent invocations return the cached value.
_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.
_getClassesReturns the class hierarchy for this object, with BaseCore being the last class in the array.
An array of classes (constructor functions), making up the class hierarchy for this object. This value is cached the first time the method, or _getAttrCfgs, is invoked. Subsequent invocations return the cached value.
_getInstanceAttrCfgsallCfgs
A helper method used to isolate the attrs config for this instance to pass to addAttrs,
from the static cached ATTRS for the class.
allCfgs
Object
The set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.
The set of attributes to be added for this instance, suitable
for passing through to addAttrs.
_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).
_initAttributeInitializes AttributeCore
_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).
_initBaseconfig
Internal construction logic for BaseCore.
config
Object
The constructor configuration object
_initHierarchyuserVals
Initializes the class hierarchy for the instance, which includes initializing attributes for each class defined in the class's static ATTRS property and invoking the initializer method on the prototype of each class in the hierarchy.
userVals
Object
Object with configuration property name/value pairs
_initHierarchyDataA helper method used by _getClasses and _getAttrCfgs, which determines both the array of classes and aggregate set of attribute configurations across the class hierarchy for the instance.
_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.
destroyDestroy lifecycle method. Invokes destructors for the class hierarchy.
A reference to this object
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.
initcfg
Init lifecycle method, invoked during construction. Sets up attributes and invokes initializers for the class hierarchy.
cfg
Object
Object with configuration property name/value pairs
A reference to this object
modifyAttrs[ctor]
configs
Provides a way to safely modify a Y.BaseCore subclass' static ATTRS
after the class has been defined or created.
BaseCore-based classes cache information about the class hierarchy in order
to efficiently create instances. This cache includes includes the aggregated
ATTRS configs. If the static ATTRS configs need to be modified after the
class has been defined or create, then use this method which will make sure
to clear any cached data before making any modifications.
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.
_allowAdHocAttrsThis property controls whether or not instances of this class should allow users to add ad-hoc attributes through the constructor configuration hash.
AdHoc attributes are attributes which are not defined by the class, and are not handled by the MyClass._NON_ATTRS_CFG
Default: undefined (false)
_ATTR_CFGThe list of properties which can be configured for each attribute (e.g. setter, getter, writeOnce, readOnly etc.)
_NON_ATTRS_CFGThe array of non-attribute configuration properties supported by this class.
For example BaseCore defines a "plugins" configuration property which
should not be set up as an attribute. This property is primarily required so
that when _allowAdHocAttrs is enabled by a class,
non-attribute configuration properties don't get added as ad-hoc attributes.
ATTRSThe default set of attributes which will be available for instances of this class, and their configuration. In addition to the configuration properties listed by AttributeCore's addAttr method, the attribute can also be configured with a "cloneDefaultValue" property, which defines how the statically defined value field should be protected ("shallow", "deep" and false are supported values).
By default if the value is an object literal or an array it will be "shallow" cloned, to protect the default value.
NAMEThe string to be used to identify instances of this class.
Classes extending BaseCore, should define their own static NAME property, which should be camelCase by convention (e.g. MyClass.NAME = "myClass";).
destroyedFlag indicating whether or not this object has been through the destroy lifecycle phase.
Default: false
destroyedChange
Fires when the value for the configuration attribute destroyed is
changed. You can listen for the event using the on method if you
wish to be notified before the attribute's value has changed, or
using the after method if you wish to be notified after the
attribute's value has changed.
e
EventFacade
initializedFlag indicating whether or not this object has been through the init lifecycle phase.
Default: false
initializedChange
Fires when the value for the configuration attribute initialized is
changed. You can listen for the event using the on method if you
wish to be notified before the attribute's value has changed, or
using the after method if you wish to be notified after the
attribute's value has changed.
e
EventFacade