flags
This module provides helpers for patterns regarding didChangeFlag events.
Contents
Module Members
Types
Module Members
PREDICATE_ANY String
Constant for the value "any". If this is used as argument to registerFlag or registerFlagFromFeature,
any flag state being true during evaluation, yields to an overall outcome of true
PREDICATE_ALL String
Constant for the value "all". If this is used as argument to registerFlag or registerFlagFromFeature,
any flag state being false during evaluation, yields to an overall outcome of false.
publisherForFeature( context, featurePath, optionalOptions )
Creates a publisher for the state of a flag, where the name of the flag is configured as widget feature.
Parameters
| Property | Type | Description |
|---|---|---|
| context | AxContext |
the widget context to work on |
| featurePath | String |
the attribute path to the configured flag within the feature map |
| optionalOptions | Object |
options for the publisher |
| optionalOptions.optional | Boolean |
if true, a missing feature configuration will result in a noop publisher. Else, a missing feature configuration results in a thrown error. Default is false |
Returns
| Type | Description |
|---|---|
Function |
the state publisher function, expecting only the new state of the flag as boolean value |
publisher( context, flagName )
Creates a publisher for the state of a flag, whose name is directly provided as argument.
Parameters
| Property | Type | Description |
|---|---|---|
| context | AxContext |
the widget context to work on |
| flagName | String |
the name of the flag |
Returns
| Type | Description |
|---|---|
Function |
the state publisher function, expecting only the new state of the flag as boolean value |
handlerFor( context )
Creates a new handler instance for didChangeFlag events, on which one can attach a listener for
accumulated flag changes. Assume for example a feature like disableOn, which defines a set of flags,
where a true state of any of the flags disables the widget. The developer shouldn't care about single
flag states but should only be notified, if a change of one flag leads to a change of the accumulated
"any flag should be true" state.
Additionally it is possible to let the handler set the current state of the accumulated flag on a given context property.
Parameters
| Property | Type | Description |
|---|---|---|
| context | AxContext |
the widget context to work on |
Returns
| Type | Description |
|---|---|
FlagHandler |
a flag handler instance |
Types
FlagHandler
FlagHandler.registerFlagFromFeature( featurePath, optionalOptions )
Registers a flag or a set of flags from the given feature. In contrast to e.g. a ResourceHandler, here
the complete attribute path to the flag(s) must be provided. This is due to the fact that there is no
convention on names for flags on a feature, as there can coexist multiple flags for one feature, each
influencing a different aspect of this feature.
Parameters
| Property | Type | Description |
|---|---|---|
| featurePath | String |
the attribute path to the configured flag(s) within the feature map |
| optionalOptions | Object, Function |
options and callbacks to use. If a function is passed, it is used as the onChange option. |
| optionalOptions.initialState | Boolean |
the optional initial state of the accumulated state. If not given, each non-inverted flag is initially assumed to be false, and true, if it is inverted |
| optionalOptions.onChange | Function, Array.<Function> |
a function or a list of functions to call whenever the accumulated state of the flags changes. It receives the new state as first argument and its previous state as second argument |
| optionalOptions.contextKey | String |
the key to set the current accumulated state on in the context. If not given, nothing happens. For example flags.myFlag would set context.flags.myFlag to the currently valid accumulated state |
| optionalOptions.predicate | String |
either #PREDICATE_ANY (default) or #PREDICATE_ALL |
Returns
| Type | Description |
|---|---|
FlagHandler |
this instance for chaining |
FlagHandler.registerFlag( possibleFlags, optionalOptions )
Registers a flag or a set of flags given as argument. Even undefined, null or an empty array
are handled gracefully and treated as an empty set of flags, thus never changing their states.
The new accumulated state is set on context.flags if that is defined. Otherwise it is set on
context.model.
Parameters
| Property | Type | Description |
|---|---|---|
| possibleFlags | String, Array.<String> |
one or a list of flags to watch |
| optionalOptions | Object, Function |
options and callbacks to use. If a function is passed, it is used as the onChange option. |
| optionalOptions.initialState | Boolean |
the optional initial state of the accumulated state. If not given each non-inverted flag is initially assumed to be false and true, if it is inverted |
| optionalOptions.onChange | Function, Array.<Function> |
a function or a list of functions to call whenever the accumuated state of the flags changes. It receives the new state as first argument and its previous state as second argument |
| optionalOptions.contextKey | String |
the key to set the current accumulated state on in the context. If not given, nothing happens. For example flags.myFlag would set context.flags.myFlag to the currently valid accumulated state |
| optionalOptions.predicate | String |
either #PREDICATE_ANY (default) or #PREDICATE_ALL |
Returns
| Type | Description |
|---|---|
FlagHandler |
this instance for chaining |