instance_script.VariableDeclaration() — svelte Function Reference

Source Code

packages/svelte/src/compiler/migrate/index.js lines 565–915

	VariableDeclaration(node, { state, path, visit, next }) {
		if (state.scope !== state.analysis.instance.scope) {
			return;
		}

		let nr_of_props = 0;

		for (let i = 0; i < node.declarations.length; i++) {
			const declarator = node.declarations[i];
			if (state.analysis.runes) {
				if (get_rune(declarator.init, state.scope) === '$props') {
					state.props_insertion_point = /** @type {number} */ (declarator.id.start) + 1;
					state.has_props_rune = true;
				}
				continue;
			}

			let bindings;
			try {
				bindings = state.scope.get_bindings(declarator);
			} catch (e) {
				// no bindings, so we can skip this
				next();
				continue;
			}
			const has_state = bindings.some((binding) => binding.kind === 'state');
			const has_props = bindings.some((binding) => binding.kind === 'bindable_prop');

			if (!has_state && !has_props) {
				next();
				continue;
			}

			if (has_props) {
				nr_of_props++;

				if (declarator.id.type !== 'Identifier') {
					// TODO invest time in this?
					throw new MigrationError(
						'Encountered an export declaration pattern that is not supported for automigration.'
					);
					// Turn export let into props. It's really really weird because export let { x: foo, z: [bar]} = ..
					// means that foo and bar are the props (i.e. the leaves are the prop names), not x and z.
					// const tmp = b.id(state.scope.generate('tmp'));
					// const paths = extract_paths(declarator.id, tmp);
					// state.props_pre.push(
					// 	b.declaration('const', tmp, visit(declarator.init!) as Expression)
					// );
					// for (const path of paths) {
					// 	const name = (path.node as Identifier).name;
					// 	const binding = state.scope.get(name)!;
					// 	const value = path.expression;
					// 	if (binding.kind === 'bindable_prop' || binding.kind === 'rest_prop') {
					// 		state.props.push({
					// 			local: name,
					// 			exported: binding.prop_alias ? binding.prop_alias : name,
					// 			init: value
					// 		});
					// 		state.props_insertion_point = /** @type {number} */(declarator.end);
					// 	} else {
					// 		declarations.push(b.declarator(path.node, value));
					// 	}
					// }
				}

				const name = declarator.id.name;
				const binding = /** @type {Binding} */ (state.scope.get(name));

				if (state.analysis.uses_props && (declarator.init || binding.updated)) {
					throw new MigrationError(
						'$$props is used together with named props in a way that cannot be automatically migrated.'
					);
				}

				const prop = state.props.find((prop) => prop.exported === (binding.prop_alias || name));
				if (prop) {
					next();
					// $$Props type was used
					prop.init = declarator.init
						? state.str
								.snip(