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Oro Frontend Development Guidelines

Oro Frontend Development Guidelines describe the Code style, a set of conventions about how to write code.

Naming Conventions

The main idea of the naming convention is to make names as informative and clear as possible.

Selector Naming

Selector names are lowercase and their logical parts are divided by a dash ().

Acceptable

product-gallery-widget

Unacceptable

productgallerywidget, productGalleryWidget, product_gallery_widget

Block Name

A block is a logical self-contained functional component of the user interface.

A block identifier should match the corresponding layout block type identifier.

Block names (a part of the block identifier) may be prefixed with a short namespace or a bundle identifier if similar blocks are provided by multiple bundles to eliminate confusion, for instance.

Examples:

product-info, shopping-cart, currency-switcher
order-group-totals and quote-group-totals, or even crm-quote-group-totals and commerce-quote-group-totals

Element Name

The namespace of an element (which us equal to the parent block ID) identifies the element as belonging to the block.

In the element identifier, the element name is delimited from the element namespace by a double underscore (**__**):

block-name\_\_elem-name

If a block has several identical elements (e.g. menu items), all of them will have the same name (e.g. menu__item).

Modifier name

The namespace of a modifier (which is equal to the parent block ID or the parent element ID) identifies the modifier as belonging to the block or the element.

The modifier name is delimited by a single underscore (_) from the modifier namespace:

  • for Boolean modifiers – owner-name_mod-name
  • for key-value type modifiers – owner-name_mod-name–mod-val

This gives the following advantages:

  • The logic of naming allows you to immediately understand what a particular class represents.
  • Decreases the likelihood of conflict between classes.
  • Each element is in the namespace.
  • Components are easily transferred from project to project.

HTML Coding Standards

Base Code Style

  1. Do not add a slash at the end of single elements.
  2. The attributes in use are ” “, not ‘ ‘.
  3. No spaces or tabs after the closing tag.
  4. Indent only with spaces.
  5. The attachment elements are indented 4 spaces.

Simple Names

<div class="product">
    <p class="product__name">Product name</p>
    <div class="product__prices">...</div>
    <div class="product__info">...</div>
</div>

The Order of the Attributes

  1. The required and optional attributes for the tag (e.g. name, type, src, href, etc).
  2. Attributes used for UI customization (e.g. class, data-*, etc).
  3. Attributes with JSON content.
<input name type id
    class
    data-*
    data-entity="{{ {
        id: entity.id,
        title: entity.title
    }|json_encode }}"
    />

CSS Coding Standards

Base Code Style

  1. Built on SASS preprocessor.
  2. Focused on web standards.

The Principles of CSS Architecture

  • Predictability — Predictability for CSS means that your rules are behaving as expected.
  • Reusable — CSS rules should be abstract and decoupled enough that you can build new components quickly from existing parts without having to recode patterns and problems you have already solved.
  • Scalable — Scalable CSS means it can be easily managed by a single person or a large engineering team.
  • Support — When new components and features need to be added, updated or rearranged on your site, doing so should not require refactoring existing CSS.
  • Responsive — We use CSS to resize, hide, shrink, enlarge, or move the content to make it look good on any screen.

SASS Code Standards

  1. Use the .scss syntax.
  2. Indentation only with spaces.
  3. Indent size: 4 spaces
  4. Continuation indent: 4 spaces
  5. The attributes in use ‘ ‘ not ” “.
  6. Use: {}, :, ;.
  7. Put a space before the opening brace { in rule declarations.
  8. Put the closing braces } of rule declarations on a new line.
  9. Each component is written in a separate file.
  10. Do not write vendors’ prefixes.

Comments

  1. Prefer line comments // to block comments.
  2. Prefer comments on their own line. Avoid end-of-line comments.
Acceptable
.element {
    // Use base color
    color: $color;
}
Unacceptable
.element {
    color: $color; /* Use base color */
}

Format

Add a space before the opening brace and a line break after. Add a line break before closing brace.

Acceptable
.element {
    color: $color;
}
Unacceptable
.element{color: $color;}

Selector delimiters

Add a line break after each selector delimiter. Delimiter should not have spaces before and after.

Acceptable
.element1,
.element2 {
     color: $color;
}
Unacceptable
.element1, .element2 {
    color: $color;
}

Type selectors

Unless necessary (for example with helper classes), do not use element names in conjunction with IDs or classes. Avoiding unnecessary ancestor selectors is useful for performance reasons.

Acceptable

.element {
    ...
}

Unacceptable

div.element {
    ...
}

div#element {
    ...
}

Combinator Indents

Use spaces before and after combinators.

Acceptable

.element1 + .element2 {
     color: $color;
}

Unacceptable

.element1+.element2 {
    color: $color;
}

Properties Line Break

Use line break for each property declaration.

Acceptable

.element {
     position: absolute;
     top: 0;
     left: 0;
}

Unacceptable

.element {
    position: absolute; top: 0; left: 0;
}

Properties Colon Indents

Use no space before property colon, and a space after.

Acceptable

.element {
    color: $color;
}

Unacceptable

.element1 {
    color : $color;
}

.element2 {
    color:$color;
}

.element3 {
    color :$color;
}

End of the Selector

Each selector should be finished with a new line.

Acceptable

.element1 {
    color: $color;
}

.element2 {
    color: $color;
}

Unacceptable

.element1 {
    color: $color;
}
.element2 {
    color: $color;
}

Shorthand

If you use more than 2 parameters (three indents, for example), write short:

.element {
    margin: 10px 0 5px;
}

If less, then:

.element {
    margin-top: 10px;
    margin-right: 2px;
}

Floating Values

For fractional numbers, do not add zero.

Acceptable

.element {
    opacity: .5;
}

Unacceptable

.element {
    opacity: 0.5;
}

Zero and Units

Omit the units for zero value.

Acceptable

.element {
    margin: 0;
}

Unacceptable

.element {
    margin: 0px;
}

Border

Use 0 instead of none to specify that a style has no border.

Acceptable

.element {
    border: 0;
}

Unacceptable

.element {
   border: none;
}

Nesting

When selectors become this long, you are likely to write CSS that is:

  • Strongly coupled to the HTML
  • Overly specific
  • Not reusable

Selector Nesting

Be careful with selector nesting. In general try to use 2 nested levels max.

Exception are pseudo elements and states.

Acceptable
.block {
    &__element {
        &--modifier {
            ...
        }
    }

    &--modifier {
        ...
    }
}
Unacceptable
.block {
    ...

    .block__element {
        ...

        &.block__element--modifier {
            // STOP!
        }
    }

    &.block--modifier {}
}

No Elements of Elements

According to BEM methodology, there are no elements of elements. It makes the elements dependent on the block only. So, you can easily move them across the block when providing changes to the interface.

Acceptable
.block {
    ...

    .block__some-element {
        ...
    }

    .block__other-element {
        ...
    }
}
Unacceptable
.block {
    ...

    .block__some-element {
        ...

        .block__some-element__other-element {
            // STOP!
        }
    }
}

Place of @media Rules

All @media rules are placed at the end of file. The block applies only to the common styles for all devices. @media describes individual styles for each type of device. This allows us in the future to change or add styles only for a specific type of device.

Acceptable

.block {
    width: 50%;
    padding: 10px;

    background-color: get-color('additional', 'middle');

    &__element {
        font-size: 12px;
    }
}

@include breakpoint('tablet') {
    .block {
        width: 100%;
    }
}

@include breakpoint('mobile') {
    .block {
        padding: 15px;

        &__element {
            font-size: 15px;
        }
    }
}

Unacceptable

.block {
    width: 50%;
    padding: 10px;

    background-color: get-color('additional', 'middle');

    @include breakpoint('tablet') {
        width: 100%;
    }

    @include breakpoint('mobile') {
        padding: 15px;
    }

    &__element {
        font-size: 12px;

        // STOP!
        @include breakpoint('mobile') {
            font-size: 15px;
        }
    }
}

Work with Colors

To work with a color, use the get-color() function, which returns a color from a predefined color scheme.

Example:

.block {
    border-color: get-color('additional', 'light');
    color: get-color('primary', 'main');
}

If you need darker or lighter or more transparent color use native Sass functions: darken(), lighten(), transparentize(), etc.

.block {
    background-color: transparentize(get-color('primary', 'main'), .8);
    border-color: darken(get-color('additional', 'light'), 10%);
    color: lighten(get-color('primary', 'main'), 10%);
}

Group Properties

Group properties are grouped in the following order:

  1. variables
  2. positioning
  3. block model
  4. typography
  5. visualization
  6. other (animation, opacity)
  7. mixins

After each group leaves behind an empty string.

In CSS, each property that can be treated in different groups depending on their use: vertical-align, overflow, clear, resize, transform.

Acceptable

// variables
$element-color: #000 !default;
$element-font: 12px !default;
$element-line-height: 1.2 !default;
.element {
    // positioning
    position: absolute;
    top: 0;
    right: 0;
    z-index: z('fixed');

    // block model
    width: 100px;
    height: 100px;
    margin: 10px;
    padding: 10px 20px;

    // typography
    font-size: $element-font;
    line-height: $element-line-height;
    text-align: center;

    // visualization
    border: 10px solid #333;
    background: red;
    color: $element-color;

    // other
    cursor: pointer;
    opacity: .2;

    // mixins
    // grouping @includes at the end makes it easier to read the entire selector.
    @include clearfix;
}

Unacceptable

.element {
    text-align: center;
    margin: 0;
    $color: #000;
    @include clearfix;
    color: $color;
    right: 0;
    position: absolute;
}

Use @extend Directive

Use @extend only selector that is a single class.

  1. Helper class include after variables.
  2. Helper class has maximum 5 rules.
  3. Helper class has abstract name and overall design style.

Examples:

$default-size: 400px !default;
$default-offset: 10px auto !default;
$default-inner-offset: 15px !default;
$default-background: #dadada !default;

%dialog {
    width: $default-size;
    margin: $default-offset;
    padding: $default-inner-offset;

    background: $default-background;
}
.modal {
    // other modal styles

    @extend %dialog;

    &__close {
        // other button styles

        @extend %dialog__close;
    }

    &__header {
        // other header styles

        @extend %background-gradient;
    }
}

Logical Sense

Use the logical number of modifiers for the element.

Acceptable

“Quiet classes”

%modifier {}
%another-modifier {}
%yet-another-modifier {}

.block {
    &__element {
        &--modifier {
            @extend %modifier;
            @extend %another-modifier;
            @extend %yet-another-modifier;
        }
    }
}
<div class="block">
    <div class="
        block__element
        block__element--modifier">
    </div>
</div>

Unacceptable

<div class="block">
    <div class="
        block__element
        block__element--modifier
        block__element--another-modifier
        block__element--yet-another-modifier">
    </div>
</div>

The Main Mixins and Functions

Helper to clear inner floats.

@mixin clearfix {
    &:after {
        content: '';

        display: block;

        clear: both;
    }
}

// use
.block {
    @include clearfix;
}

Helper for the positioning of pseudo-elements.

@mixin after {
    content: '';

    position: absolute;

    display: block;
}

// use
.block {
    //...

    &:after {
        @include after;
    }
}

Helper function for organizing z-index

@function z($layer) {
    $layers: (
        'base': 1,
        'fixed': 50,
        'dropdown': 100,
        'popup': 150,
        'hidden': -1
    );

    $z-index: map-get($layers, $layer);
    @return $z-index;
}

// use
.dialog {
    //...

    z-index: z('popup') + 1;

    &-overley {
        //...

        z-index: z('popup');
    }
}

Helper mixin for organizing @media rules

@mixin breakpoint($type) {
    $breakpoints: (
        'large': '(max-width: ' + #{$breakpoint-large} + ')',
        'tablet': '(max-width: ' + #{$breakpoint-tablet} + ')',
        'mobile': '(max-width: ' + #{$breakpoint-mobile} + ')'
    );

    @media #{map-get($breakpoints, $type)} {
        @content;
    }
}
// use

@include breakpoint('tablet') {
    // styles for tablet version
}

Best Practices

$block-font-title: 'Tahoma' !default;
$block-offset: 10px !default;
.block {
    @include clearfix;

    &__element {
        float: left;
        width: 25%;
        padding-left: $list-offset * 2;

        font-size: 14px;

        @extend %transition;

        // compound class
        &-title {
            margin-bottom: $list-offset;

            font-family: $list-font-title;
            font-size: 22px;
            line-height: 1.1;
        }

        &--first {
            padding-left: 0;
        }

        &:hover {
            border-color: get-color('additional', 'middle');
        }
    }

    &__content {
        padding: $list-offset ($list-offset * 2);
    }

    &:hover {
        background-color: get-color('secondary', 'light');
    }

    // State written &. (the active state of the menu item, for example).
    // Usually dynamic.
    &.expand {
        ...
    }
}

@include breakpoint('tablet') {
    .block {
        width: 100%;

        &__content {
            padding: $list-offset * 2;

            font-size: 15px;
        }
    }
}

@include breakpoint('mobile') {
    .block {
        &__element {
            width: 100%;

            &-title {
                margin-bottom: 0;

                font-size: 25px;
            }
        }
    }
}
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