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Migration from CSS to SASS and SMACSS

Scope

As part of our technical debt clearing exercise, we want to migrate our existing CSS to SASS and introduce a SMACSS / BEM pattern to the system. And here is my checklist.

Setup

Technical

Technically it is not a difficult exercise. SASS is backward compatible with CSS anyway. In my eyes, the difficult part is not just to get the job done but to get the job done right.

First and foremost, we changed the extensions from .css to .scss. and started compiling with compass. Previously, we did not have any lint tool for our CSS, so we picked up some syntax error or misspelling such as !impotrant, wasn't so important after all.

SMACSS and BEM

Next part is the refactoring. We opted for the SMACSS pattern because it was easy to follow and was not too much effort to implement as part of the refactoring. I would totally voted for BEM too, but it was more effort involved to change the DOM, so we left at that.

Multi Tenants

By using variables or mixins in SASS, multi-tenant projects that share the same code base or DOM elements will find that the ease of changing all base settings in one centralized _variable.scss can be very intuitive.

For example, base fonts can be changed easily without a big gun of find and replace.

$font-family-sans-serif:   'Gotham Book', Arial, Helvetica, sans-serif;
$font-family-serif:    Georgia, 'Times New Roman', serif;
$font-family-base:     $font-family-sans-serif;
And reference code will be the same across multi-tenants. 
.btn { 
  font-family: $font-family-base;
}

Mobile First

We were using the older version of bootstrap and version 4 has been and still on alpha release, so we ditched bootstrap and had a fresh start using bourbon and neat.

Instead of using media queries to target mobile audience, we took the mobile-first approach and our CSS is built on mobile experience, then using media queries to target tablet and desktop where we see fit.

For example, our mobile design for the cart page looks like this. The COLLECT IN STORE button is full width and looks fine.



However, the button is too long on desktop.


We can change the styling by using media query.

@media (min-width: 768px) {
  #clickandcollect-button {
    display: inline-block;
    width: initial;
  }
}

And the width will reset to initial depending on screen width.


SCM

If you are using any SCM, you will need to ignore the .sass-cache folder. We use git so in our .gitignore, we need to add one line.

**/.sass-cache/**

Thoughts

Migrating from CSS to SASS can be value added to any type of projects. It fits both agile or waterfall teams because CSS can fallback as SASS during the compress compilation. The code will not look too ugly and still production-worthy while migration in progress.

As part of our refactoring process, we removed all the legacy !important in CSS which was very !important for me!
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Demandware - Migration from jQuery to React

Running React only. jQuery is not defined

Scope

Our production website was using an uncompressed and unminified 7000+ lines of jQuery file that do a lot of DOM manipulation.The site was slow and a lot of overhead with the javascript.

We recently migrated our site from jQuery to React with the following goals in mind.
  • Reduce file size
  • Improve on load speed
  • DOM rendering time
  • Improve readability and maintainability of the code

7000+ lines of jQuery

React vs Angular

Perhaps one of the hardest decision I have to make is to choose between React and Angular. There are already many great articles talked about this topic and this is one of them.

The two technologies are pretty much head to head. My reason for React over Angular was more a cultural than technical reason.

Technical

Technology Stack

  • Demandware
  • React / Redux / Thunk / React Habitat
  • ES6
  • Webpack

Non-SPA

React is designed for Single Page Application, but our site is not. The complexity and integrity of an e-commerce site do not marry well with the SPA architecture.

For a non-SPA site using the React framework, javascript will throw exception if a component is not found. A SPA site will not have this issue because all components are available on the single page.

To overcome this problem, we are using the React Habitat Redux. In a nutshell, it is a layer that will help "hiding" components that are not needed for the page, thus no error for components not found.

On a typical Demandware isml page, our source code will look like this.

<isscript>
 var data = {
  "link": URLUtils.url('Cart-Show').toString(),
  "message": Resource.msg('global.notification.addtobag', 'locale', null)
 }
 var dataJson = JSON.stringify(data);
</isscript>

<div data-component="Notification_Container" data-prop-data="${dataJson}"></div>

In react, we will render our html by using this.props.

render () {
 return (
  <div className="notification-wrapper">
   <div className="message">
    {this.props.data.message}
   </div>
   <div className="action">
    <a href={this.props.data.link}>View Bag</a>
   </div>
  </div> 
 )
}

Dev tools

3rd party components

The fun part of using React is to explore 3rd party (open source) components for your need. Here is a list of some of the more important ones.

IE 10, IE 11 and Safari

Some of the ES6 commands are not supported by IE 11 and Safari. We added some polyfill to our webpack and conveniently it also works for IE 10.

IE 8 and IE 9

\@_@/

IE < 8

|Orz

Firefox

In developments, we found some of the components were not rendering in Firefox. Issues were intermittent and happening about 1 out of 10 times on a page with more data.

We webpack our js in production mode and the problem has gone away since.

Demandware Content Assets

Content assets were converted in a similar manner to other isml pages but in a better way. There are no more ad-hoc includes for random jQuery plugins. Rather, we write dedicated components to handle and support features that we want to make available to content assets.

All of these are bundled in one single bundle.js file so we can leverage client-side browser cache for performance gain.

In our content asset, we select HTML type and simply include the <div> container.

<script>
var json = {
 cid: 'my-content-asset-id',
 items: [
  {
   title: 'Do I need to be home for my delivery?',
   html: '<p>Some answers to the question...</p>'
  },
  {
   title: 'I have a Missing / Lost Order',
   html: '<p>Some more answers to another question...</p>',
  }
 ]
}
</script>

<div data-component="Your_Container_Name" data-r-prop-fields="json"></div>

Similar to what we previously done to isml, but we will use javascript json to hold all the properties by using React Habitat data-r-prop. Notice the difference in using <script> instead of <isscript> as it is not a Demandware script.

Demandware Content Slots

Content slot in Demandware is a small widget that is time-based and user segmented. For HTML type, we convert the HTML similar to content asset. For other types, they will just work fine.



One Page Checkout

Last year, we have done a Demandware - Converting Multi-steps Checkout to One Page Checkout. To convert this to React, we simply replace our jQuery.ajax() by React component with Fetch.

Google Geocoder

We use Geocoder in our store locator to display a google map for our stores. During our development, we found a race condition that sometimes the Geocoder callback is returning too late and the DOM is already re-rendered, so we wrote our own GeocoderPromise that wrapped the Google Geocoder in Promise object. 

Tealium

Some of our tags were firing off on DOM ready event, which is now lazy loading in React. We had to implement our own redux-tealium to help manually triggering tags.

Thoughts

There were a few stress points during the migration.
  • Learning curve of new technology
  • Lack of learning materials about Demandware React integration. Almost no one has done it before if asking around in Demandware XChange.
  • Using Demandware in non-SPA architecture
  • Overly complicated to do something simple (eg. show/hide elements or popup modal written in React)
Was it worth the effort? Definitely.
  • Code is now more readable and maintainable
  • Some of our jQuery plugins are overdue for updates (which we don't need to do anymore)
  • Reducing number of jQuery plugins into a handful of React components
  • No more random jQuery events firing off because hidden code buried deep somewhere
  • Significant overall performance gain


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