@lf-lang/reactor-ts/src/core/state.ts

A reactor-oriented programming framework in TypeScript

import type {Read, Write} from "./internal";

/**
 * A state variable. This class refines the Read interface by letting `get`
 * return T rather than T | Absent. If the state should be nullable or
 * uninitialized, this has to be reflected explicitly in T.
 */
export class State<T> implements Read<T>, Write<T> {
  /**
   * Create a new state variable and assign it an initial value.
   * @param value The initial value to assign to this state variable.
   */
  constructor(private value: T) {}

  /**
   * Return the current value of this state variable.
   */
  get(): T {
    return this.value;
  }

  /**
   * Set the current value of this state variable.
   * @param value
   */
  set(value: T): void {
    this.value = value;
  }
}