Enum MergeStrategy 

pub enum MergeStrategy {
    UnionConditions,
    KeepSelf,
    PanicOnConflict,
}

Strategy for handling token collisions in Classes::merge and ClassesBuilder::with_merged.

The variants differ only in what happens on a token collision; non-overlapping entries are appended in either case. UnionConditions is the Default and the recommended choice when you do not have a specific reason to pick another: it never panics (regardless of what the caller passes in) and never silently drops a caller-supplied condition.

Comparison with leptos-styles

Styles::merge in the sibling crate has a fixed override-with-fallback semantic (theme-then-user-override layering). Classes::merge instead asks the caller to choose, because classes have no values to “override” - the right behavior on collision depends entirely on the caller’s intent.

Variants

UnionConditions

On collision, replace self’s entry with one whose condition is the logical OR of both sides. The token renders when either condition is active.

Does not preserve toggle-pair structure: if either side of the collision was a toggle half, the OR produces a well-defined condition for the merged entry, but the other half of any colliding toggle is left as an orphan flat entry.

KeepSelf

On collision, drop the entry from other and leave self’s entry unchanged. Useful when self is a layered default that must win against override attempts. To get the opposite direction (other wins), call other.merge(self, MergeStrategy::KeepSelf) - this yields the same entry set with other’s conditions surviving collisions.

If a dropped entry was half of a toggle pair in other, the surviving half lands as a regular flat entry under its own reactive condition - the toggle pair is not preserved as a structural unit.

PanicOnConflict

Panic with the standard duplicate-class-token message on the first colliding entry from other. The strictest option; equivalent to manually re-adding each entry of other into self via add / add_reactive / add_toggle.

Only safe when both sides of the merge are under your own control. Avoid this strategy for any merge that combines an arbitrary classes: Classes prop with internal classes: a caller passing a colliding token would crash the component. Use UnionConditions or KeepSelf there.

Trait Implementations

impl Clone for MergeStrategy

fn clone(&self) -> MergeStrategy

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MergeStrategy

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for MergeStrategy

fn default() -> MergeStrategy

Returns the “default value” for a type.

impl PartialEq for MergeStrategy

fn eq(&self, other: &MergeStrategy) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for MergeStrategy

impl Eq for MergeStrategy

impl StructuralPartialEq for MergeStrategy