Web-Design
Monday May 24, 2021 By David Quintanilla
Use-Cases And Migration Strategies — Smashing Magazine


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Adrian Bece is a flexible fullstack net developer with in depth eCommerce expertise who’s presently working at PROTOTYP as a technical lead. He enjoys …
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Container queries have been not too long ago added to Chrome Canary and the developer group is happy in regards to the potential styling enhancements. This game-changing function brings media queries nearer to the goal parts themselves and allows them to adapt to just about any given container or format, leading to extra sturdy, reusable, and maintainable element kinds. On this article, we’re going to cowl container question fundamentals and the right way to use them at this time with progressive enhancement or polyfills.

After we write media queries for a UI ingredient, we all the time describe how that ingredient is styled relying on the display dimensions. This strategy works properly when the responsiveness of the goal ingredient media question ought to solely depend upon viewport dimension. Let’s check out the next responsive web page format instance.

Responsive page layout example. The left image shows the desktop layout at 1280px viewport width and the right image shows the mobile layout at 568px viewport width.
Responsive web page format instance. The left picture reveals the desktop format at 1280px viewport width and the best picture reveals the cell format at 568px viewport width. (Large preview)

Nonetheless, responsive Internet Design (RWD) will not be restricted to a web page format — the person UI elements often have media queries that may change their type relying on the viewport dimensions.

Responsive product card component example. The left image shows a component at 720px viewport width and the right image shows component layout at 568px viewport width.
Responsive product card element instance. The left picture reveals a element at 720px viewport width and the best picture reveals element format at 568px viewport width. (Large preview)

You may need already seen an issue with the earlier assertion — particular person UI element format usually doesn’t rely solely on the viewport dimensions. Whereas web page format is a component carefully tied to viewport dimensions and is likely one of the topmost parts in HTML, UI elements can be utilized in several contexts and containers. If you concentrate on it, the viewport is only a container, and UI elements will be nested inside different containers with kinds that have an effect on the element’s dimensions and format.

Example of page layout with the same product card UI component in the top section 3-column grid and the bottom section list.
Instance of web page format with the identical product card UI element within the high part 3-column grid and the underside part record. (Large preview)

Though the identical product card element is utilized in each the highest and backside sections, element kinds not solely depend upon the viewport dimensions but additionally depend upon the context and the container CSS properties (just like the grid within the instance) the place it’s positioned.

In fact, we will construction our CSS so we assist the type variations for various contexts and containers to handle the format challenge manually. Within the worst-case situation, this variation can be added with type override which might result in code duplication and specificity points.

.product-card {
    /* Default card type */
}

.product-card--narrow {
   /* Type variation for slender viewport and containers */
}

@media display and (min-width: 569px) {
 .product-card--wide {
     /* Type variation for wider viewport and containers */
  }
}

Nonetheless, that is extra of a workaround for the constraints of media queries quite than a correct answer. When writing media queries for UI parts we’re looking for a “magic” viewport worth for a breakpoint when the goal ingredient has minimal dimensions the place the format doesn’t break. In brief, we’re linking a “magical” viewport dimension worth to ingredient dimensions worth. This worth is often totally different from than viewport dimension and is vulnerable to bugs when interior container dimensions or format modifications.

Example of how media query cannot be reliably linked to element dimensions. Various CSS properties can affect element dimensions within a container. In this example, container padding is different between the two images.
Instance of how media question can’t be reliably linked to ingredient dimensions. Numerous CSS properties can have an effect on ingredient dimensions inside a container. On this instance, container padding is totally different between the 2 photographs. (Large preview)

The next instance showcases this actual challenge — regardless that a responsive product card ingredient has been applied and it appears good in an ordinary use-case, it appears damaged if it’s moved to a special container with CSS properties that have an effect on ingredient dimensions. Every further use-case requires further CSS code to be added which might result in duplicated code, code bloat, and code that’s tough to take care of.

See the Pen [Product cards – various containers](https://codepen.io/smashingmag/pen/abJpgvj) by Adrian Bece.

See the Pen Product cards – various containers by Adrian Bece.

This is likely one of the points that container queries making an attempt to repair. Container queries lengthen current media queries performance with queries that depend upon the goal ingredient dimensions. There are three main advantages of utilizing this strategy:

  • Container question kinds are utilized relying on the size of the goal ingredient itself. UI elements will be capable of adapt to any given context or container.
  • Builders received’t must search for a “magic quantity” viewport dimension worth that hyperlinks a viewport media question to a goal dimension of UI element in a particular container or a particular context.
  • No want so as to add further CSS lessons or media queries for various contexts and use-cases.

“The best responsive web site is a system of versatile, modular elements that may be repurposed to serve in a number of contexts.”

— “Container Queries: Once More Unto the Breach,” Mat Marquis

Earlier than we dive deep into container queries, we have to take a look at the browser assist and see how we will allow the experimental function in our browser.

Browser Help

Container queries are an experimental feature, out there presently in Chrome Canary model on the time of writing this text. If you wish to observe alongside and run the CodePen examples on this article you’ll must allow container queries within the following settings URL.

chrome://flags/#enable-container-queries
Container queries
(Large preview)

In case you’re utilizing a browser that doesn’t assist container queries, a picture showcasing the meant working instance can be offered alongside the CodePen demo.

Working With Container Queries

Container queries should not as easy as common media queries. We’ll have so as to add an additional line of CSS code to our UI ingredient to make container queries work, however there’s a motive for that and we’ll cowl that subsequent.

Containment Property

CSS include property has been added to the vast majority of trendy browsers and has an honest 75% browser support on the time of writing this text. The include property is principally used for efficiency optimization by hinting to the browser which components (subtrees) of the web page will be handled as impartial and received’t have an effect on the modifications to different parts in a tree. That means, if a change happens in a single ingredient, the browser will re-render solely that half (subtree) as an alternative of the entire web page. With include property values, we will specify which sorts of containment we need to use — format, dimension, or paint.

There are numerous great articles in regards to the include property that define out there choices and use-cases in way more element, so I’m going to focus solely on properties associated to container queries.

What does the CSS contentment property that’s used for optimization need to do with container queries? For container queries to work, the browser must know if a change happens within the ingredient’s youngsters format that it ought to re-render solely that element. The browser will know to use the code within the container question to the matching element when the element is rendered or the element’s dimension modifications.

We’ll use the format worth for the include property, however we’ll additionally want an additional value that alerts the browser in regards to the axis during which the change will happen.

  • inline-size
    Containment on the inline axis. It’s anticipated for this worth to have considerably extra use-cases, so it’s being applied first.
  • block-size
    Containment on block axis. It’s nonetheless in growth and isn’t presently out there.

One minor draw back of the include property is that our format ingredient must be a toddler of a include ingredient, that means that we’re including a further nesting stage.

<part>
  <article class="card">
      <div class="card__wrapper">
          <!-- Card content material -->       
      </div>
  </article>
</part>
.card {
   include: format inline-size;
}

.card__wrapper {
  show: grid;
  grid-gap: 1.5em;
  grid-template-rows: auto auto;
  /* ... */
}

Discover how we aren’t including this worth to a extra distant parent-like part and conserving the container as near the affected ingredient as doable.

“Efficiency is the artwork of avoiding work and making any work you do as environment friendly as doable. In lots of circumstances, it’s about working with the browser, not in opposition to it.”

— “Rendering Performance,” Paul Lewis

That’s the reason we must always accurately sign the browser in regards to the change. Wrapping a distant mother or father ingredient with a include property will be counter-productive and negatively have an effect on web page efficiency. In worst-case eventualities of misusing the include property, the format could even break and the browser received’t render it accurately.

Container Question

After the include property has been added to the cardboard ingredient wrapper, we will write a container question. We’ve added a include property to a component with card class, so now we will embody any of its baby parts in a container question.

Identical to with common media queries, we have to outline a question utilizing min-width or max-width properties and nest all selectors contained in the block. Nonetheless, we’ll be utilizing the @container key phrase as an alternative of @media to outline a container question.

@container (min-width: 568px) {
  .card__wrapper {
    align-items: middle;
    grid-gap: 1.5em;
    grid-template-rows: auto;
    grid-template-columns: 150px auto;
  }

  .card__image {
    min-width: auto;
    top: auto;
  }
}

Each card__wrapper and card__image ingredient are youngsters of card ingredient which has the include property outlined. After we exchange the common media queries with container queries, take away the extra CSS lessons for slender containers, and run the CodePen instance in a browser that helps container queries, we get the next outcome.

In this example, we’re not resizing the viewport, but the <section> container element itself that has resize CSS property applied. The component automatically switches between layouts depending on the container dimensions.
On this instance, we’re not resizing the viewport, however the <part> container ingredient itself that has resize CSS property utilized. The element robotically switches between layouts relying on the container dimensions. (Large preview)

See the Pen [Product cards – container queries](https://codepen.io/smashingmag/pen/VwpPJmO) by Adrian Bece.

See the Pen Product cards – container queries by Adrian Bece.

Please be aware that container queries presently don’t present up in Chrome developer instruments, which makes debugging container queries a bit tough. It’s anticipated that the right debugging assist can be added to the browser sooner or later.

You’ll be able to see how container queries enable us to create extra sturdy and reusable UI elements that may adapt to just about any container and format. Nonetheless, correct browser assist for container queries remains to be distant within the function. Let’s attempt to see if we will implement container queries utilizing progressive enhancement.

Progressive Enhancement & Polyfills

Let’s see if we will add a fallback to CSS class variation and media queries. We will use CSS feature queries with the @helps rule to detect out there browser options. Nonetheless, we cannot check for other queries, so we have to add a test for a include: format inline-size worth. We’ll need to assume that browsers that do assist inline-size property additionally assist container queries.

/* Examine if the inline-size worth is supported */
@helps (include: inline-size) {
  .card {
    include: format inline-size;
  }
}

/* If the inline-size worth will not be supported, use media question fallback */
@helps not (include: inline-size) {
    @media (min-width: 568px) {
       /* ... */
  }
}

/* Browser ignores @container if it’s not supported */
@container (min-width: 568px) {
  /* Container question kinds */
}

Nonetheless, this strategy may result in duplicated kinds as the identical kinds are being utilized each by container question and the media question. When you determine to implement container queries with progressive enhancement, you’d need to use a CSS pre-processor like SASS or a post-processor like PostCSS to keep away from duplicating blocks of code and use CSS mixins or one other strategy as an alternative.

See the Pen [Product cards – container queries with progressive enhancement](https://codepen.io/smashingmag/pen/MWpJMpr) by Adrian Bece.

See the Pen Product cards – container queries with progressive enhancement by Adrian Bece.

Since this container question spec remains to be in an experimental part, it’s vital to understand that the spec or implementation is inclined to alter in future releases.

Alternatively, you need to use polyfills to offer a dependable fallback. There are two JavaScript polyfills I’d like to focus on, which presently appear to be actively maintained and supply vital container question options:

Migrating From Media Queries To Container Queries

When you determine to implement container queries on an current mission that makes use of media queries, you’ll must refactor HTML and CSS code. I’ve discovered this to be the quickest and most easy means of including container queries whereas offering a dependable fallback to media queries. Let’s check out the earlier card instance.

<part>
      <div class="card__wrapper card__wrapper--wide">
          <!-- Extensive card content material -->       
      </div>
</part>

/* ... */

<apart>
      <div class="card__wrapper">
          <!-- Slender card content material -->        
      </div>
</apart>
.card__wrapper {
  show: grid;
  grid-gap: 1.5em;
  grid-template-rows: auto auto;
  /* ... */
}

.card__image {
  /* ... */
}

@media display and (min-width: 568px) {
  .card__wrapper--wide {
    align-items: middle;
    grid-gap: 1.5em;
    grid-template-rows: auto;
    grid-template-columns: 150px auto;
  }

  .card__image {
    /* ... */
  }
}

First, wrap the basis HTML ingredient that has a media question utilized to it with a component that has the include property.

<part>
  <article class="card">
      <div class="card__wrapper">
          <!-- Card content material -->        
      </div>
  </article>
</part>
@helps (include: inline-size) {
  .card {
    include: format inline-size;
  }
}

Subsequent, wrap a media question in a function question and add a container question.

@helps not (include: inline-size) {
    @media (min-width: 568px) {
    .card__wrapper--wide {
       /* ... */
    }

    .card__image {
       /* ... */
    }
  }
}


@container (min-width: 568px) {
  .card__wrapper {
     /* Identical code as .card__wrapper--wide in media question */
  }

  .card__image {
    /* Identical code as .card__image in media question */
  }
}

Though this methodology ends in some code bloat and duplicated code, by utilizing SASS or PostCSS you possibly can keep away from duplicating growth code, so the CSS supply code stays maintainable.

As soon as container queries obtain correct browser assist, you may need to think about eradicating @helps not (include: inline-size) code blocks and proceed supporting container queries solely.

Stephanie Eckles has not too long ago printed an excellent article on container queries masking numerous migration strategies. I like to recommend checking it out for extra info on the subject.

Use-Case Eventualities

As we’ve seen from the earlier examples, container queries are finest used for extremely reusable elements with a format that is determined by the out there container house and that can be utilized in numerous contexts and added to totally different containers on the web page.

Different examples embody (examples require a browser that helps container queries):

Conclusion

As soon as the spec has been applied and broadly supported in browsers, container queries may grow to be a game-changing function. It would enable builders to jot down queries on element stage, shifting the queries nearer to the associated elements, as an alternative of utilizing the distant and barely-related viewport media queries. This can end in extra sturdy, reusable, and maintainable elements that can be capable of adapt to numerous use-cases, layouts, and containers.

Because it stands, container queries are nonetheless in an early, experimental part and the implementation is inclined to alter. If you wish to begin utilizing container queries in your tasks at this time, you’ll want so as to add them utilizing progressive enhancement with function detection or use a JavaScript polyfill. Each circumstances will end in some overhead within the code, so when you determine to make use of container queries on this early part, be sure that to plan for refactoring the code as soon as the function turns into broadly supported.

References

Smashing Editorial
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