Stable API

From 1.0, a breaking change to these parts needs a major version:

• The form definition schema and its JSON Schemas (schema.json, translation.schema.json), including the meaning of built-in field types.
• The submit payload: values, keys and skipped steps.
• The @formhaus/core entries ., /server, /i18n, /fix and /cloud: exported functions, classes and types.
• FormEngine public methods and properties.
• React and Vue components, including /cloud: props, events and slots.
• The React useFormEngine hook and the Vue useFormEngine composable.
• The props a custom field component receives.
• CSS custom properties for theming.
• checkDefinition() issue codes and severities.

Not covered:

• @formhaus/core/internal.
• The editor, builder and Figma plugin.
• Warning and error message texts, fix titles and patches.
• DOM structure and CSS class names.
• @formhaus/mcp and the formhaus CLI, which have their own versions.

Before 1.0, a minor version can break these parts and lists each break in the changelog.

1.0 removes the APIs deprecated in 0.x, as announced in the changelog:

• validateDefinition from @formhaus/core. Use checkDefinition().
• The Vue submitHandler prop. Use the @submit event.

Two rules keep forms stable across minor versions:

• Custom field types named with - or :, such as x-rating, never become built-in types. See Custom field types.
• initialValues is read when the form is created, and a new definition object creates a new form. See Definition and initial values.
• keepValues and engine.replaceDefinition() are the opt-in way to change the definition and keep the answers. See Keep answers when the definition changes.