component.js — svelte Source File

Source Code

/** @import { Expression } from 'estree' */
/** @import { AST } from '#compiler' */
/** @import { AnalysisState, Context } from '../../types' */
import * as e from '../../../../errors.js';
import { get_attribute_expression, is_expression_attribute } from '../../../../utils/ast.js';
import { determine_slot } from '../../../../utils/slot.js';
import {
	validate_attribute,
	validate_attribute_name,
	validate_slot_attribute
} from './attribute.js';
import { mark_subtree_dynamic } from './fragment.js';
import { is_resolved_snippet } from './snippets.js';

/**
 * @param {AST.Component | AST.SvelteComponent | AST.SvelteSelf} node
 * @param {Context} context
 */
export function visit_component(node, context) {
	node.metadata.path = [...context.path];

	// link this node to all the snippets that it could render, so that we can prune CSS correctly
	node.metadata.snippets = new Set();

	// 'resolved' means we know which snippets this component might render. if it is `false`,
	// then `node.metadata.snippets` is populated with every locally defined snippet
	// once analysis is complete
	let resolved = true;

	for (const attribute of node.attributes) {
		if (attribute.type === 'SpreadAttribute' || attribute.type === 'BindDirective') {
			resolved = false;
			continue;
		}

		if (attribute.type !== 'Attribute' || !is_expression_attribute(attribute)) {
			continue;
		}

		const expression = get_attribute_expression(attribute);

		// given an attribute like `foo={bar}`, if `bar` resolves to an import or a prop
		// then we know it doesn't reference a locally defined snippet. if it resolves
		// to a `{#snippet bar()}` then we know _which_ snippet it resolves to. in all
		// other cases, we can't know (without much more complex static analysis) which
		// snippets the component might render, so we treat the component as unresolved
		if (expression.type === 'Identifier') {
			const binding = context.state.scope.get(expression.name);

			resolved &&= is_resolved_snippet(binding);

			if (binding?.initial?.type === 'SnippetBlock') {
				node.metadata.snippets.add(binding.initial);
			}
		} else if (expression.type !== 'Literal') {
			resolved = false;
		}
	}

	if (resolved) {
// ... (118 more lines)