Base UI Primitives

Quick Guide: Base UI is an unstyled React primitive library. Components are assembled from named parts (Root, Trigger, Portal, Positioner, Popup, Arrow), polymorphism goes through the render prop rather than asChild, state is published as data attributes and as an argument to className/style functions, and every change handler receives an eventDetails whose cancel() vetoes the change. Current: v1.7.0 — package @base-ui/react, imported per component subpath.

Detailed Resources:

• examples/core.md — part anatomy, portal containers, menus, positioning and collision handling
• examples/composition.md — both render forms, ref merging, useRender, mergeProps precedence
• examples/styling.md — attribute selectors, state functions, CSS variables, all four animation routes
• examples/state.md — controlled vs uncontrolled, eventDetails cancelation, actionsRef
• examples/forms.md — Field anatomy, validation modes, server errors, Fieldset, external runtimes
• reference.md — data-attribute and prop tables, checklists, Radix migration notes, version history

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Before writing Base UI code