GoF Command

Command.js

function copy(x) { return x; }
function cut(x) { return x; }
function paste(x) { return x; }

class Command {
    constructor (execute, value) {
        this.execute = execute;
        this.value = value;
    }
}

const CopyCommand = (value) => {
    return new Command(copy, value);
};

const CutCommand = (value) => {
    return new Command(cut, value);
};

const PasteCommand = (value) => {
    return new Command(paste, value);
};

class Input {
    constructor() {
        this.current = '';
        this.commands = [];
    }
    
    action(command) {
        const name = command.execute.toString().substr(9, 3);
        return name.charAt(0).toUpperCase() + name.slice(1);
    }
    
    execute (command) {
        this.current = command.execute(this.current, command.value);
        this.commands.push(command);
        console.log(this.action(command) + ": " + command.value);
    }
}


const input = new Input();

// issue commands

input.execute(CopyCommand('hi!'));
input.execute(CutCommand('sample text'));
input.execute(PasteCommand('ToDo'));

// Cop: hi!
// Cut: sample text
// Pas: ToDo