ExpressionItem

Creates a new object that has the same type and properties as the current SurveyJS object.

Type:

() => Base

Implemented in:

Base

The expression property. If this expression returns true, then survey will use html property to show on complete page.

Type:

string writable

This property is stored in the survey JSON definition and can be edited in the Survey Creator.

Implemented in:

ExpressionItem

Assigns a new configuration to the current SurveyJS object. This configuration is taken from a passed JSON object.

The JSON object should contain only serializable properties of this SurveyJS object. Event handlers and properties that do not belong to the SurveyJS object are ignored.

Type:

(json: any, options?: ILoadFromJSONOptions) => void

Parameters:

json, type: any ,

A JSON object with properties that you want to apply to the current SurveyJS object.

options, type: ILoadFromJSONOptions ,

An object with configuration options.

Implemented in:

Base

See also:

toJSON

Returns a JsonObjectProperty object with metadata about a serializable property that belongs to the current SurveyJS object.

If the property is not found, this method returns null.

Type:

(propName: string) => JsonObjectProperty

Parameters:

propName, type: string ,

A property name.

Implemented in:

Base

Returns the value of a property with a specified name.

If the property is not found or does not have a value, this method returns either undefined, defaultValue specified in the property configuration, or a value passed as the defaultValue parameter.

Type:

(name: string, defaultValue?: any) => any

Parameters:

name, type: string ,

A property name.

defaultValue, type: any ,

(Optional) A value to return if the property is not found or does not have a value.

Implemented in:

Base

Returns the object type as it is used in the JSON schema.

Type:

() => string

Implemented in:

Base

Returns true if the object is included in a survey.

This property may return false, for example, when you create a survey model dynamically.

Type:

boolean readonly

Implemented in:

Base

Use this method to find out if the current object is of a given typeName or inherited from it.

Type:

(typeName: string) => boolean

Parameters:

typeName, type: string ,

One of the values listed in the getType() description.

Return Value:

true if the current object is of a given typeName or inherited from it.

Implemented in:

Base

See also:

getType

Returns true if the survey is being designed in Survey Creator.

Type:

boolean readonly

Implemented in:

Base

Returns true if the object configuration is being loaded from JSON.

Type:

boolean readonly

Implemented in:

Base

Returns true if a passed value is an empty string, array, or object or if it equals to undefined or null.

Type:

(value: any, trimString?: boolean) => boolean

Parameters:

value, type: any ,

A value to be checked.

trimString, type: boolean ,

(Optional) When this parameter is true, the method ignores whitespace characters at the beginning and end of a string value. Pass false to disable this functionality.

Implemented in:

Base

An event that is raised when an ItemValue property is changed.

Parameters:

• sender: this
  A SurveyJS object whose property contains an array of ItemValue objects.
• options.obj: ItemValue
  An ItemValue object.
• options.propertyName: string
  The name of the property to which an array of ItemValue objects is assigned (for example, "choices" or "rows").
• options.name: "text" | "value"
  The name of the changed property.
• options.newValue: any
  A new value for the property.

Type:

Event<(sender: Base, options: any) => any, Base, any>

Implemented in:

Base

An event that is raised when a property of this SurveyJS object has changed.

Parameters:

• sender: this
  A SurveyJS object whose property has changed.
• options.name: string
  The name of the changed property.
• options.newValue: any
  A new value for the property.
• options.oldValue: any
  An old value of the property. If the property is an array, oldValue contains the same array as newValue does.

If you need to add and remove property change event handlers dynamically, use the registerPropertyChangedHandlers and unregisterPropertyChangedHandlers methods instead.

Type:

EventBase<Base, any>

Implemented in:

Base

Registers a single value change handler for one or multiple properties.

The registerPropertyChangedHandlers and unregisterPropertyChangedHandlers methods allow you to manage property change event handlers dynamically. If you only need to attach an event handler without removing it afterwards, you can use the onPropertyChanged event instead.

Type:

(propertyNames: string[], handler: any, key?: string) => void

Parameters:

propertyNames, type: string[] ,

An array of one or multiple property names.

handler, type: any ,

A function to call when one of the listed properties change. Accepts a new property value as an argument.

key, type: string ,

(Optional) A key that identifies the current registration. If a function for one of the properties is already registered with the same key, the function will be overwritten. You can also use the key to subsequently unregister handlers.

Implemented in:

Base

See also:

unregisterPropertyChangedHandlers

Assigns a new value to a specified property.

Type:

(name: string, val: any) => void

Parameters:

name, type: string ,

A property name.

val, type: any ,

A new value for the property.

Implemented in:

Base

Returns a JSON object that corresponds to the current SurveyJS object.

Type:

(options?: ISaveToJSONOptions) => any

Parameters:

options, type: ISaveToJSONOptions

Implemented in:

Base

See also:

fromJSON

Unregisters value change event handlers for the specified properties.

Type:

(propertyNames: string[], key?: string) => void

Parameters:

propertyNames, type: string[] ,

An array of one or multiple property names.

key, type: string ,

(Optional) A key of the registration that you want to cancel.

Implemented in:

Base

See also:

registerPropertyChangedHandlers