@northscaler/better-enum
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Better enumeration support for TypeScript than its `enum` keyword. This class is modeled after [Java's enumeration pattern](https://docs.oracle.com/javase/tutorial/java/javaOO/enum.html), where enums are instances of classes. This library provides a base
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TypeScript
/**
* Base enumeration class for the pattern where enumerated values are represented by instances of classes rather than by scalar string or numeric values alone.
*
* Every subclass `T` has the following requirements.
*
* * `T` must not be extended.
*
* * `T` must define a `private` constructor whose first two arguments are `name: string, ordinal: number`,
* * where `name` is a valid JavaScript identifier that is the same as the instance's static identifier on `T`, and
* * where `ordinal` is an integral value that is unique amongst all instances.
*
* * `T` must define a `static` method `of(it: T | string | number): T` that returns an instance of `T` whose `name` or `ordinal` is equal to the given value, or that is identical to the instance of `T` given, and must throw {@link UnidentifiableEnumerationValueError} otherwise.
*
* > NOTE: {@link Enumeration} provides a convenient function that subclasses can delegate to in order to implement the required `of` method above.
* > Use `import { _of } from '@northscaler/better-enum' and delegate the subclass's `of()` method to it.
*
* * `T` must define a `static` method `values(): T[]` that returns all instances of `T`.
* No ordering is prescribed.
* However, you can use one of the convenient sorting functions provided by this class, {@link sortByName} or {@link sortByOrdinal}, to sort the instances, or write your own.
*
* > NOTE: {@link Enumeration} provides a convenient function that subclasses can delegate to in order to implement the required `values` method above.
* > Use `import { _values } from '@northscaler/better-enum' and delegate the subclass's `values()` method to it.
*/
export declare class Enumeration<T extends Enumeration<T>> {
protected _name: string;
protected _ordinal: number;
protected _class: Function;
/**
* Constructs an enumerated value.
* @param _name The symbolic name of this instance.
* It must be a valid JavaScript symbol and must be unique amongst all instances of this class's type.
* @param _ordinal The numeric ordinal of this instance.
* It must be an integer value and must be unique amongst instances of this class's type.
* @param _class The class function of the subclass calling this constructor.
* For example, given `class Bool extends Enumeration<Bool> { ... }`, the reference to the class's function is `Bool`.
* @throws InvalidEnumerationNameError If the `_name` parameter is not a valid JavaScript identifier.
* @throws InvalidEnumerationOrdinalError If the `_ordinal` parameter is not an integer.
* @throws DuplicateEnumerationDeclarationError If there is already a value with the given `_name` or `_ordinal` amongst all instances of this class's type.
* @protected
*/
protected constructor(_name: string, _ordinal: number, _class: Function);
/**
* The symbolic name of this enumerated value.
*/
name(): string;
/**
* The integer ordinal of this enumerated value.
*/
ordinal(): number;
/**
* Returns whether the given object has the same name, ordinal & constructor name as this object.
*/
equals(that: T): boolean;
/**
* Returns the symbolic name of this enumerated value.
* @param fullyQualified Whether to return the return value of {@link toFullyQualifiedString} or just the symbolic name; defaults to `false`.
*/
toString(fullyQualified?: boolean): string;
/**
* Returns a colon-separated string of this class's name, its symbolic name, and its ordinal (like `Bool:TRUE:1`).
*/
toFullyQualifiedString(): string;
/**
* Default `toJSON()` protocol method.
* Returns the symbolic name of this enumerated value.
* @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#tojson_behavior
*
* To implement a JSON [`reviver`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#using_the_reviver_parameter), use the static `of` method defined on your class.
*/
toJSON(): string;
}
/**
* A function that attempts to locate an enumerated value given its name or ordinal.
* If given an argument that is `typeof object`, it must be an enumerated value, which is simply returned.
* Any value that is not among the symbolic names, ordinals, or instances of the enumeration class will cause this method to throw an `UnidentifiableEnumerationValueError`.
*
* This function is only intended to be used by subclasses of {@link Enumeration}.
*
* @param it The value being used to identify the enumerated value.
* @param clazz A reference to the enumeration class (if `class Foo ... {}`, then the reference `Foo` should be given).
*/
export declare function _of<T extends Enumeration<T>>(it: T | string | number, clazz: Function): T;
export declare function _values<T extends Enumeration<T>>(clazz: Function): T[];
/**
* Returns a convenient function to sort enumerations by their names.
*/
export declare const sortByName: <T extends Enumeration<T>>(a: Enumeration<T>, b: Enumeration<T>) => number;
/**
* Returns a convenient function to sort enumerations by their ordinals.
*/
export declare const sortByOrdinal: <T extends Enumeration<T>>(a: Enumeration<T>, b: Enumeration<T>) => number;