In CSS, the Flexbox layout model provides a more efficient way to lay out, align, and distribute space among items in a container, even when their size is unknown or dynamic. Flexbox is designed to provide space distribution between items in an interface and powerful alignment capabilities. However, when working with Flexbox, designers and developers sometimes wonder about the absence of justify-items and justify-self properties. This article explains why these particular properties are not part of the Flexbox module.

Understanding Flexbox Basics

Before diving into why certain properties are absent, it's important to understand some of the core concepts and properties of Flexbox:

• Flex Container: The element on which display: flex or display: inline-flex is applied. It becomes the flex container.
• Flex Items: The direct children of the flex container.
• Main Axis and Cross Axis: The main axis is the primary axis along which flex items are laid out. It can be horizontal (default) or vertical, depending on the flex-direction property. The cross axis is perpendicular to the main axis.
• justify-content: This property aligns the flex items along the main axis of the container. For example, space-between, center, flex-start, etc.
• align-items: This aligns the flex items along the cross axis of the container.
• align-self: Allows the alignment of individual flex items on the cross axis, overriding the align-items property.

Justification and Alignment in Flexbox

In Flexbox, alignment and justification properties concern themselves with the placement of flex items along the main or cross axes:

• justify-content deals with the distribution of space between and around flex items along the main axis.
• align-items and align-self deal with alignment of items along the cross axis.

Why No justify-items and justify-self?

The absence of justify-items and justify-self in Flexbox comes down to the design and intended use of the Flexbox model. The reason lies in the fact that Flexbox is primarily focused on the distribution of space in one-dimensional layouts, either along the main or cross axis.

• Redundancy: In a one-dimensional layout context, properties such as justify-content, align-items, and align-self are sufficient to handle the alignment and distribution of items along both axes. justify-items and justify-self are conceptually and functionally fit into grid layout, which handles two-dimensional layouts (both rows and columns simultaneously).
• Scope of Flexbox: Flexbox’s scope is managing layouts in a single dimension, either as a row or a column. Thus, the existing properties adequately provide the necessary controls without adding redundant or confusing options. Simply put, justify-items and justify-self are not necessary within the conceptual model of Flexbox.

Table: Flexbox Properties and Functions

Conclusion

Flexbox is designed with simplicity and efficiency in mind for laying out elements in one dimension. It does not include justify-items and justify-self because it is not necessary in a Flexbox context, where justify-content, align-items, and align-self sufficiently meet the layout requirements. Understanding these limitations and functionalities helps in effectively using CSS Flexbox to create responsive and flexible layouts.