svelte/src/compiler/phases/2-analyze/visitors/Identifier.js

Cybernetically enhanced web apps

/** @import { Expression, Identifier } from 'estree' */
/** @import { Context } from '../types' */
import is_reference from 'is-reference';
import { should_proxy } from '../../3-transform/client/utils.js';
import * as e from '../../../errors.js';
import * as w from '../../../warnings.js';
import { is_rune } from '../../../../utils.js';
import { mark_subtree_dynamic } from './shared/fragment.js';
import { get_rune } from '../../scope.js';
import { is_component_node } from '../../nodes.js';

/**
 * @param {Identifier} node
 * @param {Context} context
 */
export function Identifier(node, context) {
	let i = context.path.length;
	let parent = /** @type {Expression} */ (context.path[--i]);

	if (!is_reference(node, parent)) {
		return;
	}

	mark_subtree_dynamic(context.path);

	// If we are using arguments outside of a function, then throw an error
	if (
		node.name === 'arguments' &&
		!context.path.some((n) => n.type === 'FunctionDeclaration' || n.type === 'FunctionExpression')
	) {
		e.invalid_arguments_usage(node);
	}

	// `$$slots` exists even in runes mode
	if (node.name === '$$slots') {
		context.state.analysis.uses_slots = true;
	}

	if (context.state.analysis.runes) {
		if (
			is_rune(node.name) &&
			context.state.scope.get(node.name) === null &&
			context.state.scope.get(node.name.slice(1))?.kind !== 'store_sub'
		) {
			/** @type {Expression} */
			let current = node;
			let name = node.name;

			while (parent.type === 'MemberExpression') {
				if (parent.computed) e.rune_invalid_computed_property(parent);
				name += `.${/** @type {Identifier} */ (parent.property).name}`;

				current = parent;
				parent = /** @type {Expression} */ (context.path[--i]);

				if (!is_rune(name)) {
					if (name === '$effect.active') {
						e.rune_renamed(parent, '$effect.active', '$effect.tracking');
					}

					if (name === '$state.frozen') {
						e.rune_renamed(parent, '$state.frozen', '$state.raw');
					}

					if (name === '$state.is') {
						e.rune_removed(parent, '$state.is');
					}

					e.rune_invalid_name(parent, name);
				}
			}

			if (parent.type !== 'CallExpression') {
				e.rune_missing_parentheses(current);
			}
		}
	}

	let binding = context.state.scope.get(node.name);

	if (!context.state.analysis.runes) {
		if (node.name === '$$props') {
			context.state.analysis.uses_props = true;
		}

		if (node.name === '$$restProps') {
			context.state.analysis.uses_rest_props = true;
		}
	}

	if (binding) {
		if (context.state.expression) {
			context.state.expression.dependencies.add(binding);
			context.state.expression.references.add(binding);
			context.state.expression.has_state ||=
				binding.kind !== 'static' &&
				(binding.kind === 'prop' ||
					binding.kind === 'bindable_prop' ||
					binding.kind === 'rest_prop' ||
					!binding.is_function()) &&
				!context.state.scope.evaluate(node).is_known;
		}

		if (
			context.state.analysis.runes &&
			node !== binding.node &&
			context.state.function_depth === binding.scope.function_depth &&
			// If we have $state that can be proxied or frozen and isn't re-assigned, then that means
			// it's likely not using a primitive value and thus this warning isn't that helpful.
			((binding.kind === 'state' &&
				(binding.reassigned ||
					(binding.initial?.type === 'CallExpression' &&
						binding.initial.arguments.length === 1 &&
						binding.initial.arguments[0].type !== 'SpreadElement' &&
						!should_proxy(binding.initial.arguments[0], context.state.scope)))) ||
				binding.kind === 'raw_state' ||
				binding.kind === 'derived' ||
				binding.kind === 'prop') &&
			// We're only concerned with reads here
			(parent.type !== 'AssignmentExpression' || parent.left !== node) &&
			parent.type !== 'UpdateExpression'
		) {
			let type = 'closure';

			let i = context.path.length;
			while (i--) {
				const parent = context.path[i];

				if (
					parent.type === 'ArrowFunctionExpression' ||
					parent.type === 'FunctionDeclaration' ||
					parent.type === 'FunctionExpression'
				) {
					break;
				}

				if (
					parent.type === 'CallExpression' &&
					parent.arguments.includes(/** @type {any} */ (context.path[i + 1]))
				) {
					const rune = get_rune(parent, context.state.scope);

					if (rune === '$state' || rune === '$state.raw') {
						type = 'derived';
						break;
					}
				}
			}

			w.state_referenced_locally(node, node.name, type);
		}

		if (
			context.state.reactive_statement &&
			binding.scope === context.state.analysis.module.scope &&
			binding.reassigned
		) {
			w.reactive_declaration_module_script_dependency(node);
		}

		if (binding.metadata?.is_template_declaration && context.state.options.experimental.async) {
			let snippet_name;

			// Find out if this references a {@const ...} declaration of an implicit children snippet
			// when it is itself inside a snippet block at the same level. If so, error.
			for (let i = context.path.length - 1; i >= 0; i--) {
				const parent = context.path[i];
				const grand_parent = context.path[i - 1];

				if (parent.type === 'SnippetBlock') {
					snippet_name = parent.expression.name;
				} else if (
					snippet_name &&
					grand_parent &&
					parent.type === 'Fragment' &&
					(is_component_node(grand_parent) ||
						(grand_parent.type === 'SvelteBoundary' &&
							(snippet_name === 'failed' || snippet_name === 'pending')))
				) {
					if (
						is_component_node(grand_parent)
							? grand_parent.metadata.scopes.default === binding.scope
							: context.state.scopes.get(parent) === binding.scope
					) {
						e.const_tag_invalid_reference(node, node.name);
					} else {
						break;
					}
				}
			}
		}
	}
}