rules.js

let unlocked = {};
let inventory = {};

class Start extends Scene {
    create() {
        this.engine.setTitle(this.engine.storyData["Title"]); // TODO: replace this text using this.engine.storyData to find the story title
        this.engine.addChoice("Begin the story");
    }

    handleChoice() {
        this.engine.gotoScene(Location, this.engine.storyData["InitialLocation"]); // TODO: replace this text by the initial location of the story
    }
}

class Location extends Scene {
    create(key) {
        let locationData = key; // TODO: use `key` to get the data object for the current story location
        
        if (unlocked[locationData]) {
            console.log("In unlocked part");
            this.engine.show(this.engine.storyData["Locations"][locationData]["UnlockBody"]);
            if(this.engine.storyData["Locations"][locationData]["UnlockChoices"]) { // TODO: check if the location has any Choices
                for(let choice of this.engine.storyData["Locations"][locationData]["UnlockChoices"]) { // TODO: loop over the location's Choices
                    this.engine.addChoice(choice["Text"], choice); // TODO: use the Text of the choice
                    // TODO: add a useful second argument to addChoice so that the current code of handleChoice below works
                }
            } else {
                this.engine.addChoice("The end.")
            }

            if (this.engine.storyData["Locations"][locationData]["UnlockItems"]) {
                for (let choice of this.engine.storyData["Locations"][locationData]["UnlockItems"]) {
                    this.engine.addItem(choice["Text"], choice);
                }
            }
        } else {
            this.engine.show(this.engine.storyData["Locations"][locationData]["Body"]); // TODO: replace this text by the Body of the location data
            if(this.engine.storyData["Locations"][locationData]["Choices"]) { // TODO: check if the location has any Choices
                for(let choice of this.engine.storyData["Locations"][locationData]["Choices"]) { // TODO: loop over the location's Choices
                    this.engine.addChoice(choice["Text"], choice); // TODO: use the Text of the choice
                    // TODO: add a useful second argument to addChoice so that the current code of handleChoice below works
                }
            } else {
                this.engine.addChoice("The end.")
            }

            if (this.engine.storyData["Locations"][locationData]["Items"]) {
                for (let choice of this.engine.storyData["Locations"][locationData]["Items"]) {
                    this.engine.addItem(choice["Text"], choice);
                }
            }
        }
    }

    handleChoice(choice) {
        if(choice) {
            this.engine.show("> "+choice.Text);
            if (choice["ItemRequired"] && inventory[choice["ItemRequired"]]) {
                this.engine.gotoScene(Location, choice.ItemTarget);
            } else {
                this.engine.gotoScene(Location, choice.Target);
            }
        } else {
            this.engine.gotoScene(End);
        }
    }

    handleItem(choice) {
        if(choice["Type"] == "Unlock") {
            this.engine.show("> "+choice.Text);
            this.engine.show(choice["UseText"]);
            unlocked[choice["Result"]] = true;
            this.engine.gotoScene(Location, choice.Target);
        } else if (choice["Type"] == "Key") {
            console.log("here");
            this.engine.show("> "+choice.Text);
            this.engine.show(choice["UseText"]);
            inventory[choice["Name"]] = true;
            this.engine.gotoScene(Location, choice.Target);
        }
    }
}


class End extends Scene {
    create() {
        this.engine.show("<hr>");
        this.engine.show(this.engine.storyData.Credits);
    }
}

Engine.load(Start, 'myStory.json');