A component is a custom, self-contained HTML element. It is defined as a JavaScript class and in that class, it contains all of its functionality and the HTML code that defines it. This enables you to
The following code displays the most simple component you can create where it just renders some HTML you tell it to:
class MyCustomElement extends Monogatari.Component {
render () {
return `<h1>This is my component</h1>`;
}
}
MyCustomElement.tag = 'my-custom-element';
Now that we have our component class, we need to register it in Monogatari so it knows it exists:
monogatari.registerComponent (MyCustomElement);
And finally, just place it in our index.html with the tag we defined for it:
<my-custom-element></my-custom-element>
When monogatari gets initialized, our component will be registered and its render method will be executed, making its final HTML be:
<my-custom-element class="animated" data-component="my-custom-element">
<h1>This is my component</h1>
</my-custom-element>
The move to components
The index.html file changed significantly from Monogatari v1 to v2. Here's a comparison of what the HTML looks now and how it looked before:
That's a HUGE change right? Previously, all the HTML was right there in the index.html file and that was fine, it allowed people edit the HTML of their novel in a simple way and have a full understanding on where everything was. It also was helpful when styling because identifying all the elements and thus their selectors or even adding classes to them was a simple task.
The problems it solved
So if it was so good, why did it got changed? Well, sure, it was good but only up to a certain point.
Engine Upgrades
The main issue with having all the HTML there and allowing people to change it as they pleased was that it actually made it harder for everyone whenever a new engine version was released.
New releases often change some of that HTML, either by adding elements, removing some, editing properties or element types etc. and if game developers had changed that HTML in their games, the only way to upgrade to the new engine version was to manually review the new code, compare it with what they had and perform all the required changes to cover up for the differences which many times was not an easy task.
For example, when a bunch of data properties get changed, developers would have to go element by element changing the data properties manually which was a horrible experience for game developers and this was only part of the problem. Often developers had to edit the engine's core in order to make the HTML they added work with monogatari, making the JavaScript code another area where they had to manually see what changed and re-adapt everything every time an update got released.
Now that components are self-contained, their HTML and styling can still be changed freely by the users but whenever an engine update gets released, upgrading to it is as super simple, just having to change the monogatari core files. Even when a component's code gets changed and requires developers to update their modifications to it, it only means they'll have to change those that they actually care about instead of having to review each one of them.
Code Sharing and Re-usability
Another important issue was that it was kind of hard to share code with others or even within different games from the same developers. Since it involved changing several files core to monogatari, the process was often complex and prone to errors.
With components being self-contained, you can share it using just two files: a JavaScript file with the component class and a CSS file with its styling which people can just use in their projects by importing those files and not having to do much else.
The problems it created
This change has brought some confusion to people who expect all the HTML to be there for them to edit. It now results confusing where the code is coming from and how to update it which has caused monogatari not to be as beginner friendly as it used to be. However, I strongly believe these problems are the result of the lack of proper documentation. Components are in fact simple to use and work with, it just needs a mind shift and a proper explanation.
Changing the contents of a component
You might want to change the HTML of a component, either to add some elements for your game or because you want to change the way it looks. Every component has a render function like the one we showed in the simple example above. This function defines the default structure of any component but there are several ways to modify it.
Appending Elements
If all you want is to add some HTML element to the component, you can do so by adding your HTML in the index.html file as children of the component you want to edit. Let's retake our simple component example:
class MyCustomElement extends Monogatari.Component {
render () {
return `<h1>This is my component</h1>`;
}
}
MyCustomElement.tag = 'my-custom-element';
We already know that we need to add it in our index.html by placing the tags for it but notice how our tags are left empty, there's nothing inside of them.
<my-custom-element></my-custom-element>
When it gets rendered, the component runs its render function and places the results inside of it:
<my-custom-element class="animated" data-component="my-custom-element">
<h1>This is my component</h1>
</my-custom-element>
So now, let's say we wanted to add another element to it, a subtitle right below our h1 element we already defined. We could of course simply update our render function to include the new element:
render () {
return `
<h1>This is my component</h1>
<h2>This is my subtitle</h2>
`;
}
However, this time we were able to modify the render function because we had created our own component. What if we want to append some content to a component we didn't create like the ones monogatari ships with by default?
Well, you can just place your contents in the index.html file. Instead of leaving the component tags empty, you can place any content you want there and it will get appended to the contents of your render function:
<my-custom-element>
<h2>This is my subtitle</h2>
</my-custom-element>
Changing the Template
Some times however, the changes we want to do are more complex than simply appending something to the HTML of an element. This is where the template method that all components have by default comes in.
If you wanted to change a component, for example the game-screen element monogatari ships with, these are the steps you'd need to follow:
1. Identify the component's render method
Inside the index.js file of every component, you'll find the class that defines it and most importantly, its render method. Let's take a look at the game-screen component it's render method looks something like this (It may have changed since the writing of this documentation):
Now that we know the contents of its render method, we can create our own template to add or modify the code as we need. In our main.js, we would get the component and then, use its template method, copying the contents it currently has on the render method:
This will cause the component to use the template method we provided for it instead of the render method to get its contents giving us the freedom to modify the structure in a way almost as simple as if we had created the component ourselves.
Performing DOM Operations
A component in the end is just another HTML element, you can still perform operations over it using the DOM as you normally would. Let's try to replicate what we did to the game-screen component just using DOM operations.
Vanilla JavaScript
// Get the game-screen HTML element
const gameScreen = document.querySelector ('game-screen');
// Create the title element
const title = document.createElement ('h1');
title.innerText = 'My Title';
// Add our title
gameScreen.insertBefore (title, gameScreen.childNodes[0]);
// Get the visuals HTML element
const visuals = document.querySelector ('game-screen [data-content="visuals"]');
// Create the custom div element
const div = document.createElement ('div');
div.id = 'someCustomElement';
// Add our custom div to the visuals element
visuals.appendChild (div);
Using the Component built-in DOM Operations
// Get the game-screen Artemis element
const gameScreen = document.querySelector ('game-screen').element ();
// Add our title
gameScreen.prepend ('<h1>My Title</h1>');
// Add our custom div to the visuals element
gameScreen.content ('visuals').append ('<div id="someCustomElement"></div>');
Using Artemis
const { $_ } = Monogatari;
// Add our title
$_('game-screen').prepend ('<h1>My Title</h1>');
// Add our custom div to the visuals element
$_('game-screen [data-content="visuals"]').append ('<div id="someCustomElement"></div>');
To modify the structure of any component, we first need to know what it looks like by default. To do so, we need to dive into the code of the component we want to change, you'll find all component's in the .
Due to current limitations in the used for Monogatari's components, it is not recommended to interact with the innerHTML property of any component as it's prone to cause the duplication of the children inside such component. The approach shown here, while more verbose, avoids this situation.
The component built in operations from above actually use internally, so they're equivalent to the following code:
