azazil/inkjs

A javascript port of inkle's ink scripting language.

This is a javascript port of inkle's ink, a scripting language for writing interactive narrative.

inkjs is fully compatible with the original version, has zero dependency and works in all browsers and node.js. Please have a look at the demo!

Table of content

• Installation
• Quickstart in the browser
• Working with a JSON file
• Using Node.js
• Differences with the C# API

Installation

Grab the ink.js file from the latest release.

For npm users, install with npm install inkjs --save. Or for bower, bower install inkjs.
There's a (lighter) ES2015 version available if you only target platforms with basic ES 2015 support.
Both ink.js and ink-es2015.js use Universal Module Definition (UMD), so you can use it with RequireJS or basically any other module loader. If you don't know what any of this means, don't worry, just include ink.js with a regular script tag and everything will work fine.

Quickstart

The simplest way to get started with inkjs is to use the serverless boilerplate in the templates folder. Replace the placeholder story in story.js with your own and open index.html!

Here's what happens behind the scenes: inkjs gives you access to a global object named inkjs which has a property called Story. This is the main class we interact with.

We simply create a new story by calling var story = new inkjs.Story(storyContent); — the variable storyContent is defined in the story.js file. After that, we can use story.Continue() and story.currentChoices as described in the the official documentation.

Working with a JSON file

If you frequently need to update your story, pasting the content into story.js will probably get tedious. So another option is to dynamically load the JSON file for your story. Unfortunately, your browser won't let you do that because of CORS policy, which means you need a web server to do this. You could do this without much hassle with node.js or python for example.

Once the server is running, use the other boilerplate and place your story content inside story.json. Behind the scenes, the only difference is that we load the JSON file via ajax before creating the story:

fetch('story.json')
.then(function(response){
	return response.text();
})
.then(function(storyContent){
	story = new inkjs.Story(storyContent);
	continueStory();
});

Using node.js

You can find some boilerplate code for node.js here.

Loading inkjs

Require the module: var Story = require('inkjs').Story;.

Loading a json file

You can load the json file using a simple call to require:

var json = require('./ink_file.json');

You can also load it using fs. In that case, please note that inklecate outputs a json file encoded with BOM, and node isn't very good at handling that.

var fs = require('fs');
var json = fs.readFileSync('./ink_file.json', 'UTF-8').replace(/^\uFEFF/, '');//strips the BOM

Starting a story

Now that you have a Story object and a json file, it's time to bring it all together:

var inkStory = new Story(json);

console.log(inkStory.ContinueMaximally());
//etc

From there on, you can follow the official documentation.

Differences with the C# API

There are a few very minor API differences between ink C# and inkjs:

Getting and setting ink variables.

On platforms that do not support ES2015 Proxies (basically node.js v5, IE 11, Safari 9 and everything below), you can't directly read and write variables to the story state. Instead you will have to use the $ function:

_inkStory.variablesState.$("player_health", 100);
//instead of _inkStory.variablesState["player_health"] = 100;

var health = _inkStory.variablesState.$("player_health");
//instead of var health = _inkStory.variablesState["player_health"];

Getting the output text when calling EvaluateFunction

EvaluateFunction() lets you evaluate an ink function from within your javascript. The "normal" call is the same than in C#:

var result = EvaluateFunction("my_ink_function", ["arg1", "arg2"]);
//result is the return value of my_ink_function("arg1", "arg2")

However, if you also wish to retrieve the text that my_ink_function output, you need to call itlike this:

var result = EvaluateFunction("my_ink_function", ["arg1", "arg2"], true);
//now result is an object with two properties:
// result.returned is the return value of my_ink_function("arg1", "arg2")
// result.output is the text that was written to the output while the function was evaluated