MEDIAART 3D03: Model for an 'adventure' game

This is a basic JavaScript model for an adventure game, something like Colossal Cave Adventure (1976) or Zork (1977).

You can play Colossal Cave Adventure online here and play Zork online here. You can also play Colossal Cave Adventure on Debian Linux (or Debian Linux on WSL) by installing the bsdgames package and then launching adventure from your terminal:

sudo apt install bsdgames
adventure

The model provided here is just a starting point, and could be extended in many ways!

var world = {};
var player = { items: {} };

world.start = {
    description: "You are in a place.",
    routes: { north: "somewhereElse" },
    items: { sword: "shiny sword", shield: "wooden shield" }
};

world.somewhereElse = {
    description: "You are somewhere else, pretty different than where you started",
    routes: { south: "start" },
    items: {}
}

var place = world.start;

function go(d) {
  if(place.routes[d] != undefined) {
    const destinationName = place.routes[d];
    if(world[destinationName] != undefined) {
        place = world[destinationName];
        return place.description;
    }
    else {
        return "Uhoh you have encountered a tear in the space-time continuum.";
    }
  } else {
    return "You can't go that way.";
  }
}

function take(itemName) {
    if(place.items[itemName] != undefined) {
        const item = place.items[itemName];
        place.items[itemName] = undefined;
        player.items[itemName] = item;
        return ("You pick up the " + itemName);
    } else {
        return "There is nothing by that name here."
    }
}

// this is the main "entry-point" - it takes text entered by the player as input and returns the response to display
function respondToInput(input) {
    const cleaned = input.replaceAll("\n","");
    const words = cleaned.split(" ");
    if(words[0] == "go") {
        return go(words[1]);
    }
    else if(words[0] == "take") {
        return take(words[1]);
    }
}

We could incorporate the above model into a browser application, like example 7 from the javascript in a browser page. Or we could make a custom "REPL" (read evaluate print loop) in node.js and play the game that way. That might look like adding the following to the model/code above (which will make it only work in node.js, not the browser anymore, btw):

function myRepl(input, context, filename, callback) {
    callback(null, respondToInput(input));
}
const repl = require("repl");
console.log(place.description);
repl.start( { prompt: ">", eval: myRepl });