codesnips

command-pattern

rust 
use std::any::Any;

pub trait CommandHandler {
    fn name(&self) -> &str;

    fn handle(&self, input: &dyn Any) -> Box<dyn Any>;

Type-Erased Command Handler Registry With Trait Objects in Rust

rust trait-objects dispatch
by codesnips 3 tabs
javascript 
import { useReducer, useCallback } from 'react';

const initialState = (present) => ({ past: [], present, future: [] });

function historyReducer(state, action) {
  const { past, present, future } = state;

Build an Undo/Redo History Stack with a useHistory Reducer Hook in React

react hooks usereducer
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rust 
use std::collections::HashMap;
use serde_json::Value;

#[derive(Debug)]
pub enum DispatchError {
    UnknownCommand(String),

Compile-Time Command Dispatch Table With a Rust Declarative Macro

rust macros dispatch
by codesnips 3 tabs
typescript 
export interface DocState {
  text: string;
  selection: number;
}

export interface Command<S> {

Undo/Redo in a React Text Editor with a Command-History Stack

react hooks undo-redo
by codesnips 3 tabs