/**
 * Pure helpers behind the "Preview Code" panel: turn the current control
 * values into copy-pasteable Svelte.
 *
 * Value semantics: `undefined`/`null` means **unset** — the prop is absent and
 * the component uses its own default. An empty string is a real value and
 * renders as `name=""`.
 */
/** One attribute, formatted the way it would be written in markup. */
export declare function formatAttr(name: string, value: unknown): string;
/** The set values as an object literal for a `const args = { … }` line. */
export declare function argsObjectLiteral(props: Record<string, unknown>): string;
/** A minimal `<X …/>` when the preview has no snippet body to patch. */
export declare function generateFallbackCode(name: string, props: Record<string, unknown>, css: Record<string, string>): string;
/**
 * Make the shown code copy-pasteable: a plain {...args} spread resolves to
 * the current control values as concrete attributes; a body that uses
 * `args` in richer ways ({args.x}, foo={args}) instead gains a real
 * `const args = { … }` line, so the code always runs as written.
 */
export declare function resolveArgsInCode(body: string, props: Record<string, unknown>): string;
/**
 * Patch the snippet body with prop/CSS changes from Controls: the root
 * component tag gains, updates — and, for props unset since the initial
 * args, loses — attributes.
 */
export declare function patchSnippetCode(snippetBody: string, name: string, currentProps: Record<string, unknown>, currentCss: Record<string, string>, initialProps: Record<string, unknown>, initialCss: Record<string, string>): string;