Installation

$ npm install fxos-fastlist

Usage

<fxos-fastlist>
  <template>
    <li>
      <h3>${title}</h3>
      <p>${body}</p>
    </li>
  </template>
</fxos-fastlist>

var list = document.querySelector('fxos-fastlist');

// triggers render
list.setModel([
  { title: 'Title 1', body: 'Body 1' },
  { title: 'Title 2', body: 'Body 2' },
  { title: 'Title 3', body: 'Body 3' },
  ...
);

Sections

To group list-items into sections, define a getSectionName() function before assigning a model.

list.configure({
  getSectionName: function(item) {
    return item.section;
  }
});

list.setModel([
  { title: 'Title 1', body: 'Body 1', section: 1 },
  { title: 'Title 2', body: 'Body 2', section: 1 },
  { title: 'Title 3', body: 'Body 3', section: 2 },
  ...
];

Images

GaiaFastList takes care of rendering images for you to ensure that scrolling performance remains fast.

Place <div class="image"><img/></div> as the first child of your list-item template.

<fxos-fastlist>
  <template>
    <li>
      <div class="image"><img/></div>
      <h3>${title}</h3>
      <p>${body}</p>
    </li>
  </template>
</fxos-fastlist>

Then define a .getItemImageSrc() function that returns either a String or a Blob, sync or async (by returning a Promise).

list.configure({
  getItemImageSrc(item) { return item.src; }
});

Caching

The optional caching feature will cache rendered list-items and section HTML in localStorage. On second render we inject the cached HTML right away for a really fast first-paint. This way the user see some content right away, giving you time to fetch your model behind the scenes.

<fxos-fastlist caching>
  <template>
    ...
  </template>
</fxos-fastlist>

list.setModel([...]);

// update the cached content
list.cache();

// you can clear caches if need be
list.clearCache();

Optimizing reflows

Defining top and bottom offsets avoids the component having to read dimensions from the DOM, which can be costly. The following example is for a list that occupies the entire vertical screen space.

<fxos-fastlist top="0" bottom="0">
  <template>
    ...
  </template>
</fxos-fastlist>

Offsetting content

Sometimes you may require elements other than list-items within your scrollable region (eg. a search field). The offset attribute allows you to define a value which all list content will be offset by. The value should usually be the height of your 'foreign' element.

<fxos-fastlist offset="50">
  <div style="height: 50px"></div>
  <template>
    ...
  </template>
</fxos-fastlist>

Developing locally

1. git clone https://github.com/fxos-components/fxos-fastlist.git
2. cd fxos-checkbox
3. npm install (NPM3)
4. npm start

Readiness

• [ ] Accessibility
• [ ] Localization
• [ ] Performance
• [ ] Visual/UX
• [ ] RTL

Tests

1. Ensure Firefox Nightly is installed on your machine.
2. $ npm install
3. $ npm test

If your would like tests to run on file change use:

$ npm run test-dev

Lint check

Run lint check with command:

$ npm run lint