Version 3.18.1
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BaseCore Class

Module: base-core
Parent Module: base

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:

  1. It impacts components which may have 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).

  1. Extension developers may need to move code from Extension constructors to initializers

Older 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.

Constructor

BaseCore

(
  • cfg
)

Parameters:

  • cfg Object

    Object with configuration property name/value pairs. The object can be used to provide initial values for the objects published attributes.

Methods

_addAttrs

(
  • cfgs
  • values
  • lazy
)
private

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).

Parameters:

  • 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.

_addLazyAttr

(
  • name
  • [lazyCfg]
)
private

Finishes initializing an attribute which has been lazily added.

Parameters:

  • name Object

    The name of the attribute

  • [lazyCfg] Object optional

    Optional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained lazy config from state.

_addOutOfOrder

(
  • name
  • cfg
)
private

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: ...
                 }
            });

Parameters:

  • name String

    attribute name

  • cfg Object

    attribute configuration

_aggregateAttrs

(
  • allAttrs
)
Object private

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).

Parameters:

  • allAttrs Array

    An array of ATTRS definitions across classes in the hierarchy (subclass first, Base last)

Returns:

Object:

The aggregate set of ATTRS definitions for the instance

_attrCfgHash

() private

Utility method to define the attribute hash used to filter/whitelist property mixes for this class for iteration performance reasons.

_baseDestroy

() private

Internal destroy implementation for BaseCore

_baseInit

() private

Internal initialization implementation for BaseCore

_cloneDefaultValue

(
  • cfg
)
private

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.

Parameters:

_destroyHierarchy

() private

Destroys the class hierarchy for this instance by invoking the destructor method on the prototype of each class in the hierarchy.

_filterAdHocAttrs

(
  • allAttrs
  • userVals
)
Object private

Parameters:

  • 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.

Returns:

Object:

The set of adhoc attributes passed in, in the form of an object with attribute name/configuration pairs.

_getAttr

(
  • name
)
Any protected chainable

Provides the common implementation for the public get method, allowing Attribute hosts to over-ride either method.

See get for argument details.

Parameters:

  • name String

    The name of the attribute.

Returns:

Any:

The value of the attribute.

_getAttrCfgs

() Object protected

Returns an aggregated set of attribute configurations, by traversing the class hierarchy.

Returns:

Object:

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.

_getAttrInitVal

(
  • attr
  • cfg
  • initValues
)
Any private

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.

Parameters:

  • attr String

    The name of the attribute

  • cfg Object

    The attribute configuration object

  • initValues Object

    The object with simple and complex attribute name/value pairs returned from _normAttrVals

Returns:

Any:

The initial value of the attribute.

_getAttrs

(
  • attrs
)
Object protected

Implementation behind the public getAttrs method, to get multiple attribute values.

Parameters:

  • attrs String[] | Boolean

    Optional. An array of attribute names. If omitted, all attribute values are returned. If set to true, all attributes modified from their initial values are returned.

Returns:

Object:

An object with attribute name/value pairs.

_getClasses

() Function[] protected

Returns the class hierarchy for this object, with BaseCore being the last class in the array.

Returns:

Function[]:

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.

_getInstanceAttrCfgs

(
  • allCfgs
)
Object private

A helper method used to isolate the attrs config for this instance to pass to addAttrs, from the static cached ATTRS for the class.

Parameters:

  • 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.

Returns:

Object:

The set of attributes to be added for this instance, suitable for passing through to addAttrs.

_getStateVal

(
  • name
  • [cfg]
)
Any private

Gets the stored value for the attribute, from either the internal state object, or the state proxy if it exits

Parameters:

  • name String

    The name of the attribute

  • [cfg] 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.

Returns:

Any:

The stored value of the attribute

_initAttrHost

(
  • attrs
  • values
  • lazy
)
private

Constructor logic for attributes. Initializes the host state, and sets up the inital attributes passed to the constructor.

Parameters:

  • 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).

_initAttribute

() private

Initializes AttributeCore

_initAttrs

(
  • attrs
  • values
  • lazy
)
protected

Utility method to set up initial attributes defined during construction, either through the constructor.ATTRS property, or explicitly passed in.

Parameters:

  • 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).

_initBase

(
  • config
)
private

Internal construction logic for BaseCore.

Parameters:

  • config Object

    The constructor configuration object

_initHierarchy

(
  • userVals
)
private

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.

Parameters:

  • userVals Object

    Object with configuration property name/value pairs

_initHierarchyData

() private

A 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.

_isLazyAttr

(
  • name
)
Boolean private

Checks whether or not the attribute is one which has been added lazily and still requires initialization.

Parameters:

  • name String

    The name of the attribute

Returns:

Boolean:

true if it's a lazily added attribute, false otherwise.

_normAttrVals

(
  • valueHash
)
Object private

Utility method to normalize attribute values. The base implementation simply merges the hash to protect the original.

Parameters:

  • valueHash Object

    An object with attribute name/value pairs

Returns:

Object:

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.

_protectAttrs

(
  • attrs
)
Object deprecated protected

Inherited from AttributeCore: attribute/js/AttributeCore.js:901

Deprecated: Use `AttributeCore.protectAttrs()` or `Attribute.protectAttrs()` which are the same static utility method.

Utility method to protect an attribute configuration hash, by merging the entire object and the individual attr config objects.

Parameters:

  • attrs Object

    A hash of attribute to configuration object pairs.

Returns:

Object:

A protected version of the attrs argument.

_set

(
  • name
  • val
  • [opts]
)
Object protected chainable

Allows setting of readOnly/writeOnce attributes. See set for argument details.

Parameters:

  • name String

    The name of the attribute.

  • val Any

    The value to set the attribute to.

  • [opts] Object optional

    Optional data providing the circumstances for the change.

Returns:

Object:

A reference to the host object.

_setAttr

(
  • name
  • value
  • [opts]
  • force
)
Object protected chainable

Provides the common implementation for the public set and protected _set methods.

See set for argument details.

Parameters:

  • name String

    The name of the attribute.

  • value Any

    The value to set the attribute to.

  • [opts] Object optional

    Optional data providing the circumstances for the change.

  • force Boolean

    If true, allows the caller to set values for readOnly or writeOnce attributes which have already been set.

Returns:

Object:

A reference to the host object.

_setAttrs

(
  • attrs
  • [opts]
)
Object protected chainable

Implementation behind the public setAttrs method, to set multiple attribute values.

Parameters:

  • attrs Object

    An object with attributes name/value pairs.

  • [opts] Object optional

    Optional data providing the circumstances for the change

Returns:

Object:

A reference to the host object.

_setAttrVal

(
  • attrName
  • subAttrName
  • prevVal
  • newVal
  • [opts]
  • [attrCfg]
)
Boolean private

Updates the stored value of the attribute in the privately held State object, if validation and setter passes.

Parameters:

  • 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.

Returns:

Boolean:

true if the new attribute value was stored, false if not.

_setStateVal

(
  • name
  • value
)
private

Sets the stored value for the attribute, in either the internal state object, or the state proxy if it exits

Parameters:

  • name String

    The name of the attribute

  • value Any

    The value of the attribute

addAttr

(
  • name
  • config
  • lazy
)
Object chainable

Adds an attribute with the provided configuration to the host object.

The config argument object supports the following properties:

value <Any>
The initial value to set on the attribute
valueFn <Function | String>

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.

readOnly <boolean>
Whether or not the attribute is read only. Attributes having readOnly set to true cannot be modified by invoking the set method.
writeOnce <boolean> or <string>
Whether or not the attribute is "write once". Attributes having writeOnce set to true, can only have their values set once, be it through the default configuration, constructor configuration arguments, or by invoking set.

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)

setter <Function | String>

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.

getter <Function | String>

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.

validator <Function | String>

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.

lazyAdd <boolean>
Whether or not to delay initialization of the attribute until the first call to get/set it. This flag can be used to over-ride lazy initialization on a per attribute basis, when adding multiple attributes through the addAttrs method.

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.

Parameters:

  • 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).

Returns:

Object:

A reference to the host object.

addAttrs

(
  • cfgs
  • values
  • lazy
)
Object chainable

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.

Parameters:

  • 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.

Returns:

Object:

A reference to the host object.

attrAdded

(
  • name
)
Boolean

Checks if the given attribute has been added to the host

Parameters:

  • name String

    The name of the attribute to check.

Returns:

Boolean:

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.

destroy

() BaseCore chainable

Destroy lifecycle method. Invokes destructors for the class hierarchy.

Returns:

BaseCore:

A reference to this object

get

(
  • name
)
Any

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.

Parameters:

  • 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"))

Returns:

Any:

The value of the attribute

getAttrs

(
  • attrs
)
Object

Gets multiple attribute values.

Parameters:

  • attrs String[] | Boolean

    Optional. An array of attribute names. If omitted, all attribute values are returned. If set to true, all attributes modified from their initial values are returned.

Returns:

Object:

An object with attribute name/value pairs.

init

(
  • cfg
)
BaseCore chainable

Init lifecycle method, invoked during construction. Sets up attributes and invokes initializers for the class hierarchy.

Parameters:

  • cfg Object

    Object with configuration property name/value pairs

Returns:

BaseCore:

A reference to this object

modifyAttrs

(
  • [ctor]
  • configs
)
static

Defined in base/js/BaseCore.js:227

Available since 3.10.0

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.

Parameters:

  • [ctor] Function optional

    The constructor function whose ATTRS should be modified. If a ctor function is not specified, then this is assumed to be the constructor which hosts the ATTRS.

  • configs Object

    The collection of ATTRS configs to mix with the existing attribute configurations.

set

(
  • name
  • value
  • [opts]
)
Object chainable

Sets the value of an attribute.

Parameters:

  • 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.

Returns:

Object:

A reference to the host object.

setAttrs

(
  • attrs
  • [opts]
)
Object chainable

Sets multiple attribute values.

Parameters:

  • attrs Object

    An object with attributes name/value pairs.

  • [opts] Object optional

    Optional data providing the circumstances for the change.

Returns:

Object:

A reference to the host object.

toString

() String

Default toString implementation. Provides the constructor NAME and the instance guid, if set.

Returns:

String:

String representation for this object

Properties

_allowAdHocAttrs

Boolean protected

This 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_CFG

Array private static

The list of properties which can be configured for each attribute (e.g. setter, getter, writeOnce, readOnly etc.)

_NON_ATTRS_CFG

Array private static

The 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.

ATTRS

Object static

The 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.

NAME

String static

The 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";).

name

String deprecated

Defined in base/js/BaseCore.js:297

Deprecated: Use this.constructor.NAME

The string used to identify the class of this object.

Attributes

destroyed

Boolean readonly

Flag indicating whether or not this object has been through the destroy lifecycle phase.

Default: false

Fires event 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.

Parameters:

  • e EventFacade
    An Event Facade object with the following attribute-specific properties added:
    • prevVal Any
      The value of the attribute, prior to it being set.
    • newVal Any
      The value the attribute is to be set to.
    • attrName String
      The name of the attribute being set.
    • subAttrName String
      If setting a property within the attribute's value, the name of the sub-attribute property being set.

initialized

Boolean readonly

Flag indicating whether or not this object has been through the init lifecycle phase.

Default: false

Fires event 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.

Parameters:

  • e EventFacade
    An Event Facade object with the following attribute-specific properties added:
    • prevVal Any
      The value of the attribute, prior to it being set.
    • newVal Any
      The value the attribute is to be set to.
    • attrName String
      The name of the attribute being set.
    • subAttrName String
      If setting a property within the attribute's value, the name of the sub-attribute property being set.