Scrollytelling Template
A component-based rich media / scrollytelling template made with Svelte. (View demo).
The easiest way to build a project from this template is to clone it using degit, which just creates a local copy of the files (not a Git branch). You can also hack it live here.
Getting started
If you don't have degit, you can install it from NPM.
npm install -g degit
Then run the following command to clone this template (replace your-project with a name for your project folder).
degit ONSvisual/svelte-scrolly your-project
Next, open the folder and install the dependencies to get started.
cd your-project
npm install
You can then start a local development server to see live changes as you edit the template. It will run on http://localhost:5000/ and should update every time you save changes to a file.
npm run dev
Finally. When you're done creating your project, you can compile it. (You'll find the compiled code in the public folder).
npm run build
How to edit
It should be possible to start hacking this template without knowing Svelte, but if you want to go further, it's worth working through their tutorial.
For the most part, you shouldn't need to edit anything outside of the /src folder. Most of the code you'll need to edit is contained in the App.svelte file, which contains all of the HTML structure and content, as well as some JS functions to initialise the interactive elements. You'll also probably need to edit config.js, and may want to add your own functions to utils.js. The rest of the source files are the components, which are unlikley to need editing.
If you need to add images or data files for charts, maps, etc, you can put these directly into the img and data folder within the /public folder (where the compiled code will go). This folder also contains an index.html file, where you'll want to edit the title and meta tags.
About the components
<ONSHeader/> & <ONSFooter/>
Minimal ONS-branded page headers and footers based on existing ONS templates.
<Header/>
A full height component for the top of the article, with an optional background image which can be static (as in the demo) or scroll with the text.
<Section/>
Unstyled component. Mostly for text content, but can take any HTML if needed.
<Media/>
Used to create DIVS for content within a responsive grid (for maps, charts, images etc). It also allows for full width media. See the default template for options.
<Scroller/>
This is a really important component that allows for dynamic scroll-triggered content with interactions coded in Javascript. It is coded by Rich Harris (the creator of Svelte), and is documented here, but has been re-styled with CSS in this template (see notes below).
<Filler/>
This is for full screen captions etc, typically used to introduce an article or to provide a break/transition between sections.
<Divider/>
A horizontal divider that can be used between sections. You can also use it as a blank spacer by calling it with the hr parameter disabled, like this <Divider hr={false}/>
Other notes
Theming and styling
The demo has two built-in colour themes ("light" and "dark"), defined at the top of the src/config.js file. You can also add your own themes here. One theme is selected at the top of the App.svelte file, but can be overridden on individual components by adding a theme parameter. Eg. <Divider theme="dark"/>.
The global styling for the template is contained in the public/global.css file. This shouldn't need to be edited, but you may want to make use of the classes that it contains.
If you need to add component-specific styling within your project, you can do this by adding classes within the <style></style> tags of the App.svelte file, or by using inline styles.
Using the <Scroller/> component
This component will take a bit of time to get your head around. Within each Scoller component you'll find two parent elements, <div slot="background"/> and <div slot="foreground">. The background div contains the full-screen map, chart or media that you are animating/manipulating, and the foreground slot contains a series of <section/> elements, which contain the text captions.
The essential thing to understand is that each section is automatically tracked and bound to an index value (in Javascript), starting from zero. In the demo, these indices are bound to an array, and each Scroller has an associated array of Javascript functions (there are two in the demo, chartActions and mapActions) that control the interactions for each caption. If there is no interaction for a particular caption, then it needs a null value in this array, or a repetion of the previous function (depending what interaction you need).
The Scroller component has other features not used in the demo, including tracking the exact progress between captions, or within a whole Scroller section, which can be used for more complex continuous interactions (rather than step-based). All of the features are documented here.
