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Layout Primitives

Stack, Cluster, and Center cover the flexbox layouts you write constantly while keeping markup Bootstrap-native and dependency-free.

Quick Start

from faststrap import Stack, Cluster, Center, Button

Stack(
    "Profile",
    "Billing",
    "Security",
    gap=3,
)

Cluster(
    Button("Save", variant="primary"),
    Button("Cancel", variant="secondary", outline=True),
    justify="end",
)

Center(
    "Nothing selected yet",
    min_height="40vh",
    max_width="32rem",
)

Parameters

Component Key Parameters Notes
Stack gap, align, justify Vertical d-flex flex-column composition.
Cluster gap, align, justify, wrap Horizontal action rows, filter chips, and toolbar groups.
Center min_height, max_width, text_center Empty states, hero copy, and centered panels.

All three accept **kwargs, including cls, id, style, hx_*, data_*, and aria_* attributes.

Notes

  • These are intentionally zero-JS and use Bootstrap utility classes.
  • gap maps to Bootstrap's gap-* scale.
  • align maps to align-items-*; justify maps to justify-content-*.

API Reference

faststrap.components.layout.primitives.Stack(*children, gap=UNSET, align=UNSET, justify=UNSET, **kwargs)

Render a vertical flex stack with a Bootstrap gap scale.

Source code in src/faststrap/components/layout/primitives.py 
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@register(category="layout")
@beta
def Stack(
    *children: Any,
    gap: int | str | None = UNSET,
    align: Align | None = UNSET,
    justify: Justify | None = UNSET,
    **kwargs: Any,
) -> Div:
    """Render a vertical flex stack with a Bootstrap gap scale."""
    cfg = resolve_defaults("Stack", gap=gap, align=align, justify=justify)
    c_gap = cfg.get("gap")
    if c_gap is None:
        c_gap = 3
    c_align = cfg.get("align")
    c_justify = cfg.get("justify")

    user_cls = kwargs.pop("cls", "")
    attrs: dict[str, Any] = {
        "cls": merge_classes(
            "d-flex flex-column",
            f"gap-{c_gap}",
            _align_class(c_align),
            _justify_class(c_justify),
            user_cls,
        )
    }
    attrs.update(convert_attrs(kwargs))
    return Div(*children, **attrs)

faststrap.components.layout.primitives.Cluster(*children, gap=UNSET, align=UNSET, justify=UNSET, wrap=UNSET, **kwargs)

Render a horizontal wrapping cluster for action rows and chips.

Source code in src/faststrap/components/layout/primitives.py 
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@register(category="layout")
@beta
def Cluster(
    *children: Any,
    gap: int | str | None = UNSET,
    align: Align | None = UNSET,
    justify: Justify | None = UNSET,
    wrap: bool | None = UNSET,
    **kwargs: Any,
) -> Div:
    """Render a horizontal wrapping cluster for action rows and chips."""
    cfg = resolve_defaults("Cluster", gap=gap, align=align, justify=justify, wrap=wrap)
    c_gap = cfg.get("gap")
    if c_gap is None:
        c_gap = 2
    c_align = cfg.get("align") or "center"
    c_justify = cfg.get("justify")
    c_wrap = cfg.get("wrap")
    if c_wrap is None:
        c_wrap = True

    user_cls = kwargs.pop("cls", "")
    attrs: dict[str, Any] = {
        "cls": merge_classes(
            "d-flex",
            "flex-wrap" if c_wrap else "flex-nowrap",
            f"gap-{c_gap}",
            _align_class(c_align),
            _justify_class(c_justify),
            user_cls,
        )
    }
    attrs.update(convert_attrs(kwargs))
    return Div(*children, **attrs)

faststrap.components.layout.primitives.Center(*children, min_height=UNSET, max_width=UNSET, text_center=UNSET, **kwargs)

Render content centered on both axes.

Source code in src/faststrap/components/layout/primitives.py 
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@register(category="layout")
@beta
def Center(
    *children: Any,
    min_height: str | None = UNSET,
    max_width: str | None = UNSET,
    text_center: bool | None = UNSET,
    **kwargs: Any,
) -> Div:
    """Render content centered on both axes."""
    cfg = resolve_defaults(
        "Center",
        min_height=min_height,
        max_width=max_width,
        text_center=text_center,
    )
    c_min_height = cfg.get("min_height")
    c_max_width = cfg.get("max_width")
    c_text_center = cfg.get("text_center")
    if c_text_center is None:
        c_text_center = True

    user_cls = kwargs.pop("cls", "")
    user_style = kwargs.pop("style", None)
    styles: list[str] = []
    if c_min_height:
        styles.append(f"min-height: {c_min_height};")
    if c_max_width:
        styles.append(f"max-width: {c_max_width}; margin-inline: auto;")

    attrs: dict[str, Any] = {
        "cls": merge_classes(
            "d-flex align-items-center justify-content-center",
            "text-center" if c_text_center else "",
            user_cls,
        )
    }
    if styles or user_style:
        attrs["style"] = _merge_style(" ".join(styles), user_style)
    attrs.update(convert_attrs(kwargs))
    return Div(*children, **attrs)