Method Overview

Method Details

aliasOf(propertyName){Function}

A property decorator that creates a two-way binding between the property it decorates and an inner property of one of its members.

Parameter:

propertyName String The aliased property name.

Returns:

Type	Description
Function	The property decorator.

Examples:

// property example
@aliasOf("viewModel.name")
name: string = "name";

// method example
@aliasOf("viewModel.someMethod")
someMethod: () => string;

cast(propertyName){Function}

This method decorator is used to define the method that will cast a property from a class.

Parameter:

propertyName String The property name the function will cast.

Returns:

Type	Description
Function	The method descriptor.

See also:

• Accessor

Example:

import Accessor from "esri/core/Accessor";
import { subclass, property, cast } from "esri/core/tsSupport/declare";

@subclass()
class Color extends Accessor {

  @property()
  r: number = 0;

  @property()
  g: number = 0;

  @property()
  b: number = 0;

  @property()
  a: number = 1;

  @cast("r")
  @cast("g")
  @cast("b")
  protected castComponent(value) {
    // cast method that clamp the value that
    // will be set on r, g or b between 0 and 255
    return Math.max(0, Math.min(255, value));
  }

  @cast("a")
  protected castAlpha(value) {
    // cast method that clamp the value that
    // will be set on a between 0 and 255
    return Math.max(0, Math.min(1, value));
  }
}

cast(functionOrClass){Function}

This property decorator is used to define the function or class for a property.

Parameter:

functionOrClass Function The function or class to cast the property

Returns:

Type	Description
Function	The property descriptor.

See also:

• Accessor

Example:

import Accessor from "esri/core/Accessor";
import { subclass, property, cast } from "esri/core/tsSupport/declare";

function clampRGB(component: number) {
  return Math.min(Math.max(component, 0), 255);
}

function clampAlpha(alpha: number) {
  return Math.min(Math.max(alpha, 0), 1);
}

@subclass()
class Color extends Accessor {

  @property()
  @cast(clampRGB)
  r: number = 0;

  @property()
  @cast(clampRGB)
  g: number = 0;

  @property()
  @cast(clampRGB)
  b: number = 0;

  @property()
  @cast(clampRGB)
  a: number = 1;
}

declared(baseClass, mixinClasses){*}

Deprecated since version 4.16. declared() is not needed to extend Accessor anymore. See Implementing Accessor for updated information.

A function that can be used as a class. It extends expression and is used in conjunction with the @subclass decorator to create a class compatible to dojo.declare. Please refer to the subclass documentation for further information.

Parameters:

baseClass The class to extend.

mixinClasses Object repeatable The mixin classes used to extend the base class.

Returns:

Type	Description
*	The first baseClass.

Example:

// typescript syntax which creates a subclass that extends the Accessor class.
@subclass("my.custom.class")
class MyCustomClass extends declared(Accessor) {
  // ...
}

property(propertyMetadata){Function}

This convenience decorator is used to define an Accessor property. Any property defined with this decorator can now be get and set. In addition, you can watch for any property changes. Many times this decorator is used in conjunction with the @renderable decorator.

Parameters:

Specification:

propertyMetadata Object optional An object describing the property. Specification: dependsOn String[] optional Property names of dependencies. type Function optional The constructor used to autocast the property. cast Function optional The function to use to autocast the property. Alternative to define the type. The function is called with the value set by the user and should return the cast value. readOnly Boolean optional Default Value: false Indicates whether the property is read-only. constructOnly Boolean optional Default Value: false Indicates whether the property can be set during construction but is otherwise read-only. aliasOf String optional The property decorator that creates a two-way binding between the property it decorates and an inner property of one of its members. value Object optional The default value for the property.

Returns:

Type	Description
Function	The property descriptor.

See also:

• Accessor

Example:

// typescript syntax to specify the property.
@property()
title: string = "Awesome Title!"

subclass(declaredClass){Function}

Parameter:

declaredClass String optional The subclass name.

Returns:

Type	Description
Function	The class decorator.

Example:

// Typescript syntax which creates a subclass that extends the Accessor class.
@subclass("my.custom.class")
class MyCustomClass extends Accessor {
  // ...
}