svelte
Version:
Cybernetically enhanced web apps
114 lines (93 loc) • 2.83 kB
JavaScript
/** @import { AST, Binding } from '#compiler' */
/** @import { Scope } from '../../scope' */
/** @import { Context } from '../types' */
import { validate_block_not_empty, validate_opening_tag } from './shared/utils.js';
import * as e from '../../../errors.js';
/**
* @param {AST.SnippetBlock} node
* @param {Context} context
*/
export function SnippetBlock(node, context) {
context.state.analysis.snippets.add(node);
validate_block_not_empty(node.body, context);
if (context.state.analysis.runes) {
validate_opening_tag(node, context.state, '#');
}
for (const arg of node.parameters) {
if (arg.type === 'RestElement') {
e.snippet_invalid_rest_parameter(arg);
}
}
context.next({ ...context.state, parent_element: null });
const can_hoist =
context.path.length === 1 &&
context.path[0].type === 'Fragment' &&
can_hoist_snippet(context.state.scope, context.state.scopes);
const name = node.expression.name;
if (can_hoist) {
const binding = /** @type {Binding} */ (context.state.scope.get(name));
context.state.analysis.module.scope.declarations.set(name, binding);
} else {
const undefined_export = context.state.analysis.undefined_exports.get(name);
if (undefined_export) {
e.snippet_invalid_export(undefined_export);
}
}
node.metadata.can_hoist = can_hoist;
const { path } = context;
const parent = path.at(-2);
if (!parent) return;
if (
parent.type === 'Component' &&
parent.attributes.some(
(attribute) =>
(attribute.type === 'Attribute' || attribute.type === 'BindDirective') &&
attribute.name === node.expression.name
)
) {
e.snippet_shadowing_prop(node, node.expression.name);
}
if (node.expression.name !== 'children') return;
if (
parent.type === 'Component' ||
parent.type === 'SvelteComponent' ||
parent.type === 'SvelteSelf'
) {
if (
parent.fragment.nodes.some(
(node) =>
node.type !== 'SnippetBlock' &&
(node.type !== 'Text' || node.data.trim()) &&
node.type !== 'Comment'
)
) {
e.snippet_conflict(node);
}
}
}
/**
* @param {Map<AST.SvelteNode, Scope>} scopes
* @param {Scope} scope
*/
function can_hoist_snippet(scope, scopes, visited = new Set()) {
for (const [reference] of scope.references) {
const binding = scope.get(reference);
if (!binding || binding.scope.function_depth === 0) {
continue;
}
// ignore bindings declared inside the snippet (e.g. the snippet's own parameters)
if (binding.scope.function_depth >= scope.function_depth) {
continue;
}
if (binding.initial?.type === 'SnippetBlock') {
if (visited.has(binding)) continue;
visited.add(binding);
const snippet_scope = /** @type {Scope} */ (scopes.get(binding.initial));
if (can_hoist_snippet(snippet_scope, scopes, visited)) {
continue;
}
}
return false;
}
return true;
}