ImmutableValue class
📖 Description
The ImmutableValue class defines an immutable version of a Value instance. An ImmutableValue instance is obtained using the immutableValueOf method of a Context or using the immutable property of a Value.
🗃️ Fields
🏷️ context
Retrieves the context identifier for the value where * is the global (root) context.
Type
"*" | string
🏷️ hasValue
Retrieves if there is a value set.
Type
boolean
🏷️ isLocked
Retrieves if the value is locked (write-protected).
Type
boolean
🏷️ isModified
Retrieves if the value is modified.
Type
boolean
🏷️ isSealed
Retrieves if the value is sealed. A value is considered sealed when the form respondent has seen/answered the block and is past the section that contains the block that denotes this value. Only sealed values can be considered as confirmed by the form respondent. If a value is not sealed, it is not exportable.
Type
boolean
🏷️ key
Retrieves a unique key for the value within its context (the key is prefixed with an underscore).
Type
string
🏷️ reference
Retrieves the optional reference. This reference is used by some blocks to store an additional identifier related to the value. For example, when a value from a dropdown block is set, the reference is used to store the identifier of the selected item.
Type
string | undefined
🏷️ slot
Retrieves a reference to the slot that defines the value.
Type
🏷️ string
Retrieves the value as a string.
Type
string
🏷️ time
Retrieves the timestamp of the last value update as the number of milliseconds since the ECMAScript epoch.
Type
number | undefined
🏷️ value
Retrieves the typed value.
The type T is the value type denoted by the Slot type of the value.
Type
T
▶️ Methods
🔧 subscribe
Subscribe to value changes using the given context.
Signature
subscribe(fnChange: (value: Value) => void, context?: {}): this
Parameters
| Name | Type | Optional | Description |
|---|---|---|---|
fnChange | (value: Value) => void | No | Specifies the function that is invoked when the value is changed. |
context | {} | Yes | Specifies the context. |
Return value
Returns a reference to the ImmutableValue instance.
🔧 unsubscribe
Unsubscribe the given context from the ImmutableValue instance.
Signature
unsubscribe(context?: {}): this
Parameters
| Name | Type | Optional | Description |
|---|---|---|---|
context | {} | Yes | Specifies the context. If omitted all subscribers are unsubscribed. |
Return value
Returns a reference to the ImmutableValue instance.