svelte
Version:
Cybernetically enhanced web apps
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JavaScript
/** @import { Expression, Node, Program } from 'estree' */
/** @import { Binding, AST, ValidatedCompileOptions, ValidatedModuleCompileOptions } from '#compiler' */
/** @import { AnalysisState, Visitors } from './types' */
/** @import { Analysis, ComponentAnalysis, Js, ReactiveStatement, Template } from '../types' */
import { walk } from 'zimmerframe';
import * as e from '../../errors.js';
import * as w from '../../warnings.js';
import { extract_identifiers, is_text_attribute } from '../../utils/ast.js';
import * as b from '../../utils/builders.js';
import { Scope, ScopeRoot, create_scopes, get_rune, set_scope } from '../scope.js';
import check_graph_for_cycles from './utils/check_graph_for_cycles.js';
import { create_attribute, is_custom_element_node } from '../nodes.js';
import { analyze_css } from './css/css-analyze.js';
import { prune } from './css/css-prune.js';
import { hash, is_rune } from '../../../utils.js';
import { warn_unused } from './css/css-warn.js';
import { extract_svelte_ignore } from '../../utils/extract_svelte_ignore.js';
import { ignore_map, ignore_stack, pop_ignore, push_ignore } from '../../state.js';
import { ArrowFunctionExpression } from './visitors/ArrowFunctionExpression.js';
import { AssignmentExpression } from './visitors/AssignmentExpression.js';
import { Attribute } from './visitors/Attribute.js';
import { AwaitBlock } from './visitors/AwaitBlock.js';
import { BindDirective } from './visitors/BindDirective.js';
import { CallExpression } from './visitors/CallExpression.js';
import { ClassBody } from './visitors/ClassBody.js';
import { ClassDeclaration } from './visitors/ClassDeclaration.js';
import { ClassDirective } from './visitors/ClassDirective.js';
import { Component } from './visitors/Component.js';
import { ConstTag } from './visitors/ConstTag.js';
import { DebugTag } from './visitors/DebugTag.js';
import { EachBlock } from './visitors/EachBlock.js';
import { ExportDefaultDeclaration } from './visitors/ExportDefaultDeclaration.js';
import { ExportNamedDeclaration } from './visitors/ExportNamedDeclaration.js';
import { ExportSpecifier } from './visitors/ExportSpecifier.js';
import { ExpressionStatement } from './visitors/ExpressionStatement.js';
import { ExpressionTag } from './visitors/ExpressionTag.js';
import { FunctionDeclaration } from './visitors/FunctionDeclaration.js';
import { FunctionExpression } from './visitors/FunctionExpression.js';
import { HtmlTag } from './visitors/HtmlTag.js';
import { Identifier } from './visitors/Identifier.js';
import { IfBlock } from './visitors/IfBlock.js';
import { ImportDeclaration } from './visitors/ImportDeclaration.js';
import { KeyBlock } from './visitors/KeyBlock.js';
import { LabeledStatement } from './visitors/LabeledStatement.js';
import { LetDirective } from './visitors/LetDirective.js';
import { MemberExpression } from './visitors/MemberExpression.js';
import { NewExpression } from './visitors/NewExpression.js';
import { OnDirective } from './visitors/OnDirective.js';
import { RegularElement } from './visitors/RegularElement.js';
import { RenderTag } from './visitors/RenderTag.js';
import { SlotElement } from './visitors/SlotElement.js';
import { SnippetBlock } from './visitors/SnippetBlock.js';
import { SpreadAttribute } from './visitors/SpreadAttribute.js';
import { SpreadElement } from './visitors/SpreadElement.js';
import { StyleDirective } from './visitors/StyleDirective.js';
import { SvelteBody } from './visitors/SvelteBody.js';
import { SvelteComponent } from './visitors/SvelteComponent.js';
import { SvelteDocument } from './visitors/SvelteDocument.js';
import { SvelteElement } from './visitors/SvelteElement.js';
import { SvelteFragment } from './visitors/SvelteFragment.js';
import { SvelteHead } from './visitors/SvelteHead.js';
import { SvelteSelf } from './visitors/SvelteSelf.js';
import { SvelteWindow } from './visitors/SvelteWindow.js';
import { SvelteBoundary } from './visitors/SvelteBoundary.js';
import { TaggedTemplateExpression } from './visitors/TaggedTemplateExpression.js';
import { Text } from './visitors/Text.js';
import { TitleElement } from './visitors/TitleElement.js';
import { TransitionDirective } from './visitors/TransitionDirective.js';
import { UpdateExpression } from './visitors/UpdateExpression.js';
import { UseDirective } from './visitors/UseDirective.js';
import { VariableDeclarator } from './visitors/VariableDeclarator.js';
import is_reference from 'is-reference';
import { mark_subtree_dynamic } from './visitors/shared/fragment.js';
/**
* @type {Visitors}
*/
const visitors = {
_(node, { state, next, path }) {
const parent = path.at(-1);
/** @type {string[]} */
const ignores = [];
if (parent?.type === 'Fragment' && node.type !== 'Comment' && node.type !== 'Text') {
const idx = parent.nodes.indexOf(/** @type {any} */ (node));
for (let i = idx - 1; i >= 0; i--) {
const prev = parent.nodes[i];
if (prev.type === 'Comment') {
ignores.push(
...extract_svelte_ignore(
prev.start + 4 /* '<!--'.length */,
prev.data,
state.analysis.runes
)
);
} else if (prev.type !== 'Text') {
break;
}
}
} else {
const comments = /** @type {any} */ (node).leadingComments;
if (comments) {
for (const comment of comments) {
ignores.push(
...extract_svelte_ignore(
comment.start + 2 /* '//'.length */,
comment.value,
state.analysis.runes
)
);
}
}
}
if (ignores.length > 0) {
push_ignore(ignores);
}
ignore_map.set(node, structuredClone(ignore_stack));
const scope = state.scopes.get(node);
next(scope !== undefined && scope !== state.scope ? { ...state, scope } : state);
if (ignores.length > 0) {
pop_ignore();
}
},
ArrowFunctionExpression,
AssignmentExpression,
Attribute,
AwaitBlock,
BindDirective,
CallExpression,
ClassBody,
ClassDeclaration,
ClassDirective,
Component,
ConstTag,
DebugTag,
EachBlock,
ExportDefaultDeclaration,
ExportNamedDeclaration,
ExportSpecifier,
ExpressionStatement,
ExpressionTag,
FunctionDeclaration,
FunctionExpression,
HtmlTag,
Identifier,
IfBlock,
ImportDeclaration,
KeyBlock,
LabeledStatement,
LetDirective,
MemberExpression,
NewExpression,
OnDirective,
RegularElement,
RenderTag,
SlotElement,
SnippetBlock,
SpreadAttribute,
SpreadElement,
StyleDirective,
SvelteBody,
SvelteComponent,
SvelteDocument,
SvelteElement,
SvelteFragment,
SvelteHead,
SvelteSelf,
SvelteWindow,
SvelteBoundary,
TaggedTemplateExpression,
Text,
TransitionDirective,
TitleElement,
UpdateExpression,
UseDirective,
VariableDeclarator
};
/**
* @param {AST.Script | null} script
* @param {ScopeRoot} root
* @param {boolean} allow_reactive_declarations
* @param {Scope | null} parent
* @returns {Js}
*/
function js(script, root, allow_reactive_declarations, parent) {
/** @type {Program} */
const ast = script?.content ?? {
type: 'Program',
sourceType: 'module',
start: -1,
end: -1,
body: []
};
const { scope, scopes } = create_scopes(ast, root, allow_reactive_declarations, parent);
return { ast, scope, scopes };
}
/**
* @param {string} filename
*/
function get_component_name(filename) {
const parts = filename.split(/[/\\]/);
const basename = /** @type {string} */ (parts.pop());
const last_dir = /** @type {string} */ (parts.at(-1));
let name = basename.replace('.svelte', '');
if (name === 'index' && last_dir && last_dir !== 'src') {
name = last_dir;
}
return name[0].toUpperCase() + name.slice(1);
}
const RESERVED = ['$$props', '$$restProps', '$$slots'];
/**
* @param {Program} ast
* @param {ValidatedModuleCompileOptions} options
* @returns {Analysis}
*/
export function analyze_module(ast, options) {
const { scope, scopes } = create_scopes(ast, new ScopeRoot(), false, null);
for (const [name, references] of scope.references) {
if (name[0] !== '$' || RESERVED.includes(name)) continue;
if (name === '$' || name[1] === '$') {
e.global_reference_invalid(references[0].node, name);
}
const binding = scope.get(name.slice(1));
if (binding !== null && !is_rune(name)) {
e.store_invalid_subscription_module(references[0].node);
}
}
/** @type {Analysis} */
const analysis = {
module: { ast, scope, scopes },
name: options.filename,
accessors: false,
runes: true,
immutable: true,
tracing: false
};
walk(
/** @type {Node} */ (ast),
{
scope,
scopes,
analysis: /** @type {ComponentAnalysis} */ (analysis),
derived_state: [],
// TODO the following are not needed for modules, but we have to pass them in order to avoid type error,
// and reducing the type would result in a lot of tedious type casts elsewhere - find a good solution one day
ast_type: /** @type {any} */ (null),
component_slots: new Set(),
expression: null,
function_depth: 0,
has_props_rune: false,
options: /** @type {ValidatedCompileOptions} */ (options),
parent_element: null,
reactive_statement: null
},
visitors
);
return analysis;
}
/**
* @param {AST.Root} root
* @param {string} source
* @param {ValidatedCompileOptions} options
* @returns {ComponentAnalysis}
*/
export function analyze_component(root, source, options) {
const scope_root = new ScopeRoot();
const module = js(root.module, scope_root, false, null);
const instance = js(root.instance, scope_root, true, module.scope);
const { scope, scopes } = create_scopes(root.fragment, scope_root, false, instance.scope);
/** @type {Template} */
const template = { ast: root.fragment, scope, scopes };
let synthetic_stores_legacy_check = [];
// create synthetic bindings for store subscriptions
for (const [name, references] of module.scope.references) {
if (name[0] !== '$' || RESERVED.includes(name)) continue;
if (name === '$' || name[1] === '$') {
e.global_reference_invalid(references[0].node, name);
}
const store_name = name.slice(1);
const declaration = instance.scope.get(store_name);
const init = /** @type {Node | undefined} */ (declaration?.initial);
// If we're not in legacy mode through the compiler option, assume the user
// is referencing a rune and not a global store.
if (
options.runes === false ||
!is_rune(name) ||
(declaration !== null &&
// const state = $state(0) is valid
(get_rune(init, instance.scope) === null ||
// rune-line names received as props are valid too (but we have to protect against $props as store)
(store_name !== 'props' && get_rune(init, instance.scope) === '$props')) &&
// allow `import { derived } from 'svelte/store'` in the same file as `const x = $derived(..)` because one is not a subscription to the other
!(
name === '$derived' &&
declaration.initial?.type === 'ImportDeclaration' &&
declaration.initial.source.value === 'svelte/store'
))
) {
let is_nested_store_subscription_node = undefined;
search: for (const reference of references) {
for (let i = reference.path.length - 1; i >= 0; i--) {
const scope =
scopes.get(reference.path[i]) ||
module.scopes.get(reference.path[i]) ||
instance.scopes.get(reference.path[i]);
if (scope) {
const owner = scope?.owner(store_name);
if (!!owner && owner !== module.scope && owner !== instance.scope) {
is_nested_store_subscription_node = reference.node;
break search;
}
break;
}
}
}
if (is_nested_store_subscription_node) {
e.store_invalid_scoped_subscription(is_nested_store_subscription_node);
}
if (options.runes !== false) {
if (declaration === null && /[a-z]/.test(store_name[0])) {
e.global_reference_invalid(references[0].node, name);
} else if (declaration !== null && is_rune(name)) {
for (const { node, path } of references) {
if (path.at(-1)?.type === 'CallExpression') {
w.store_rune_conflict(node, store_name);
}
}
}
}
if (module.ast) {
for (const { node, path } of references) {
// if the reference is inside module, error. this is a bit hacky but it works
if (
/** @type {number} */ (node.start) > /** @type {number} */ (module.ast.start) &&
/** @type {number} */ (node.end) < /** @type {number} */ (module.ast.end) &&
// const state = $state(0) is valid
get_rune(/** @type {Node} */ (path.at(-1)), module.scope) === null
) {
e.store_invalid_subscription(node);
}
}
}
// we push to the array because at this moment in time we can't be sure if we are in legacy
// mode yet because we are still changing the module scope
synthetic_stores_legacy_check.push(() => {
// if we are creating a synthetic binding for a let declaration we should also declare
// the declaration as state in case it's reassigned and we are not in runes mode (the function will
// not be called if we are not in runes mode, that's why there's no !runes check here)
if (
declaration !== null &&
declaration.kind === 'normal' &&
declaration.declaration_kind === 'let' &&
declaration.reassigned
) {
declaration.kind = 'state';
}
});
const binding = instance.scope.declare(b.id(name), 'store_sub', 'synthetic');
binding.references = references;
instance.scope.references.set(name, references);
module.scope.references.delete(name);
}
}
const component_name = get_component_name(options.filename);
const runes = options.runes ?? Array.from(module.scope.references.keys()).some(is_rune);
if (!runes) {
for (let check of synthetic_stores_legacy_check) {
check();
}
}
if (runes && root.module) {
const context = root.module.attributes.find((attribute) => attribute.name === 'context');
if (context) {
w.script_context_deprecated(context);
}
}
// TODO remove all the ?? stuff, we don't need it now that we're validating the config
/** @type {ComponentAnalysis} */
const analysis = {
name: module.scope.generate(options.name ?? component_name),
root: scope_root,
module,
instance,
template,
elements: [],
runes,
tracing: false,
immutable: runes || options.immutable,
exports: [],
uses_props: false,
props_id: null,
uses_rest_props: false,
uses_slots: false,
uses_component_bindings: false,
uses_render_tags: false,
needs_context: false,
needs_props: false,
event_directive_node: null,
uses_event_attributes: false,
custom_element: options.customElementOptions ?? options.customElement,
inject_styles: options.css === 'injected' || options.customElement,
accessors: options.customElement
? true
: (runes ? false : !!options.accessors) ||
// because $set method needs accessors
options.compatibility?.componentApi === 4,
reactive_statements: new Map(),
binding_groups: new Map(),
slot_names: new Map(),
css: {
ast: root.css,
hash: root.css
? options.cssHash({
css: root.css.content.styles,
filename: options.filename,
name: component_name,
hash
})
: '',
keyframes: []
},
source,
undefined_exports: new Map(),
snippet_renderers: new Map(),
snippets: new Set()
};
if (!runes) {
// every exported `let` or `var` declaration becomes a prop, everything else becomes an export
for (const node of instance.ast.body) {
if (node.type !== 'ExportNamedDeclaration') continue;
analysis.needs_props = true;
if (node.declaration) {
if (
node.declaration.type === 'FunctionDeclaration' ||
node.declaration.type === 'ClassDeclaration'
) {
analysis.exports.push({
name: /** @type {import('estree').Identifier} */ (node.declaration.id).name,
alias: null
});
} else if (node.declaration.type === 'VariableDeclaration') {
if (node.declaration.kind === 'const') {
for (const declarator of node.declaration.declarations) {
for (const node of extract_identifiers(declarator.id)) {
analysis.exports.push({ name: node.name, alias: null });
}
}
} else {
for (const declarator of node.declaration.declarations) {
for (const id of extract_identifiers(declarator.id)) {
const binding = /** @type {Binding} */ (instance.scope.get(id.name));
binding.kind = 'bindable_prop';
}
}
}
}
} else {
for (const specifier of node.specifiers) {
if (specifier.local.type !== 'Identifier' || specifier.exported.type !== 'Identifier') {
continue;
}
const binding = instance.scope.get(specifier.local.name);
if (
binding &&
(binding.declaration_kind === 'var' || binding.declaration_kind === 'let')
) {
binding.kind = 'bindable_prop';
if (specifier.exported.name !== specifier.local.name) {
binding.prop_alias = specifier.exported.name;
}
} else {
analysis.exports.push({ name: specifier.local.name, alias: specifier.exported.name });
}
}
}
}
// if reassigned/mutated bindings are referenced in `$:` blocks
// or the template, turn them into state
for (const binding of instance.scope.declarations.values()) {
if (binding.kind !== 'normal') continue;
for (const { node, path } of binding.references) {
if (node === binding.node) continue;
if (binding.updated) {
if (
path[path.length - 1].type === 'StyleDirective' ||
path.some((node) => node.type === 'Fragment') ||
(path[1].type === 'LabeledStatement' && path[1].label.name === '$')
) {
binding.kind = 'state';
}
}
}
}
// more legacy nonsense: if an `each` binding is reassigned/mutated,
// treat the expression as being mutated as well
walk(/** @type {AST.SvelteNode} */ (template.ast), null, {
EachBlock(node) {
const scope = /** @type {Scope} */ (template.scopes.get(node));
for (const binding of scope.declarations.values()) {
if (binding.updated) {
const state = { scope: /** @type {Scope} */ (scope.parent), scopes: template.scopes };
walk(node.expression, state, {
// @ts-expect-error
_: set_scope,
Identifier(node, context) {
const parent = /** @type {Expression} */ (context.path.at(-1));
if (is_reference(node, parent)) {
const binding = context.state.scope.get(node.name);
if (
binding &&
binding.kind === 'normal' &&
binding.declaration_kind !== 'import'
) {
binding.kind = 'state';
binding.mutated = true;
}
}
}
});
break;
}
}
}
});
}
if (root.options) {
for (const attribute of root.options.attributes) {
if (attribute.name === 'accessors' && analysis.runes) {
w.options_deprecated_accessors(attribute);
}
if (attribute.name === 'customElement' && !options.customElement) {
w.options_missing_custom_element(attribute);
}
if (attribute.name === 'immutable' && analysis.runes) {
w.options_deprecated_immutable(attribute);
}
}
}
if (analysis.runes) {
const props_refs = module.scope.references.get('$$props');
if (props_refs) {
e.legacy_props_invalid(props_refs[0].node);
}
const rest_props_refs = module.scope.references.get('$$restProps');
if (rest_props_refs) {
e.legacy_rest_props_invalid(rest_props_refs[0].node);
}
for (const { ast, scope, scopes } of [module, instance, template]) {
/** @type {AnalysisState} */
const state = {
scope,
scopes,
analysis,
options,
ast_type: ast === instance.ast ? 'instance' : ast === template.ast ? 'template' : 'module',
parent_element: null,
has_props_rune: false,
component_slots: new Set(),
expression: null,
derived_state: [],
function_depth: scope.function_depth,
reactive_statement: null
};
walk(/** @type {AST.SvelteNode} */ (ast), state, visitors);
}
// warn on any nonstate declarations that are a) reassigned and b) referenced in the template
for (const scope of [module.scope, instance.scope]) {
outer: for (const [name, binding] of scope.declarations) {
if (binding.kind === 'normal' && binding.reassigned) {
inner: for (const { path } of binding.references) {
if (path[0].type !== 'Fragment') continue;
for (let i = 1; i < path.length; i += 1) {
const type = path[i].type;
if (
type === 'FunctionDeclaration' ||
type === 'FunctionExpression' ||
type === 'ArrowFunctionExpression'
) {
continue inner;
}
// bind:this doesn't need to be a state reference if it will never change
if (
type === 'BindDirective' &&
/** @type {AST.BindDirective} */ (path[i]).name === 'this'
) {
for (let j = i - 1; j >= 0; j -= 1) {
const type = path[j].type;
if (
type === 'IfBlock' ||
type === 'EachBlock' ||
type === 'AwaitBlock' ||
type === 'KeyBlock'
) {
w.non_reactive_update(binding.node, name);
continue outer;
}
}
continue inner;
}
}
w.non_reactive_update(binding.node, name);
continue outer;
}
}
}
}
} else {
instance.scope.declare(b.id('$$props'), 'rest_prop', 'synthetic');
instance.scope.declare(b.id('$$restProps'), 'rest_prop', 'synthetic');
for (const { ast, scope, scopes } of [module, instance, template]) {
/** @type {AnalysisState} */
const state = {
scope,
scopes,
analysis,
options,
parent_element: null,
has_props_rune: false,
ast_type: ast === instance.ast ? 'instance' : ast === template.ast ? 'template' : 'module',
reactive_statement: null,
component_slots: new Set(),
expression: null,
derived_state: [],
function_depth: scope.function_depth
};
walk(/** @type {AST.SvelteNode} */ (ast), state, visitors);
}
for (const [name, binding] of instance.scope.declarations) {
if (
(binding.kind === 'prop' || binding.kind === 'bindable_prop') &&
binding.node.name !== '$$props'
) {
const references = binding.references.filter(
(r) => r.node !== binding.node && r.path.at(-1)?.type !== 'ExportSpecifier'
);
if (!references.length && !instance.scope.declarations.has(`$${name}`)) {
w.export_let_unused(binding.node, name);
}
}
}
analysis.reactive_statements = order_reactive_statements(analysis.reactive_statements);
}
for (const node of analysis.module.ast.body) {
if (node.type === 'ExportNamedDeclaration' && node.specifiers !== null && node.source == null) {
for (const specifier of node.specifiers) {
if (specifier.local.type !== 'Identifier') continue;
const binding = analysis.module.scope.get(specifier.local.name);
if (!binding) e.export_undefined(specifier, specifier.local.name);
}
}
}
if (analysis.event_directive_node && analysis.uses_event_attributes) {
e.mixed_event_handler_syntaxes(
analysis.event_directive_node,
analysis.event_directive_node.name
);
}
for (const [node, resolved] of analysis.snippet_renderers) {
if (!resolved) {
node.metadata.snippets = analysis.snippets;
}
for (const snippet of node.metadata.snippets) {
snippet.metadata.sites.add(node);
}
}
if (
analysis.uses_render_tags &&
(analysis.uses_slots || (!analysis.custom_element && analysis.slot_names.size > 0))
) {
const pos = analysis.slot_names.values().next().value ?? analysis.source.indexOf('$$slot');
e.slot_snippet_conflict(pos);
}
if (analysis.css.ast) {
analyze_css(analysis.css.ast, analysis);
// mark nodes as scoped/unused/empty etc
for (const node of analysis.elements) {
prune(analysis.css.ast, node);
}
const { comment } = analysis.css.ast.content;
const should_ignore_unused =
comment &&
extract_svelte_ignore(comment.start, comment.data, analysis.runes).includes(
'css_unused_selector'
);
if (!should_ignore_unused) {
warn_unused(analysis.css.ast);
}
}
for (const node of analysis.elements) {
if (node.metadata.scoped && is_custom_element_node(node)) {
mark_subtree_dynamic(node.metadata.path);
}
let has_class = false;
let has_style = false;
let has_spread = false;
let has_class_directive = false;
let has_style_directive = false;
for (const attribute of node.attributes) {
// The spread method appends the hash to the end of the class attribute on its own
if (attribute.type === 'SpreadAttribute') {
has_spread = true;
break;
} else if (attribute.type === 'Attribute') {
has_class ||= attribute.name.toLowerCase() === 'class';
has_style ||= attribute.name.toLowerCase() === 'style';
} else if (attribute.type === 'ClassDirective') {
has_class_directive = true;
} else if (attribute.type === 'StyleDirective') {
has_style_directive = true;
}
}
// We need an empty class to generate the set_class() or class="" correctly
if (!has_spread && !has_class && (node.metadata.scoped || has_class_directive)) {
node.attributes.push(
create_attribute('class', -1, -1, [
{
type: 'Text',
data: '',
raw: '',
start: -1,
end: -1
}
])
);
}
// We need an empty style to generate the set_style() correctly
if (!has_spread && !has_style && has_style_directive) {
node.attributes.push(
create_attribute('style', -1, -1, [
{
type: 'Text',
data: '',
raw: '',
start: -1,
end: -1
}
])
);
}
}
// TODO
// analysis.stylesheet.warn_on_unused_selectors(analysis);
return analysis;
}
/**
* @param {Map<import('estree').LabeledStatement, ReactiveStatement>} unsorted_reactive_declarations
*/
function order_reactive_statements(unsorted_reactive_declarations) {
/** @typedef {[import('estree').LabeledStatement, ReactiveStatement]} Tuple */
/** @type {Map<string, Array<Tuple>>} */
const lookup = new Map();
for (const [node, declaration] of unsorted_reactive_declarations) {
for (const binding of declaration.assignments) {
const statements = lookup.get(binding.node.name) ?? [];
statements.push([node, declaration]);
lookup.set(binding.node.name, statements);
}
}
/** @type {Array<[string, string]>} */
const edges = [];
for (const [, { assignments, dependencies }] of unsorted_reactive_declarations) {
for (const assignment of assignments) {
for (const dependency of dependencies) {
if (!assignments.has(dependency)) {
edges.push([assignment.node.name, dependency.node.name]);
}
}
}
}
const cycle = check_graph_for_cycles(edges);
if (cycle?.length) {
const declaration = /** @type {Tuple[]} */ (lookup.get(cycle[0]))[0];
e.reactive_declaration_cycle(declaration[0], cycle.join(' → '));
}
// We use a map and take advantage of the fact that the spec says insertion order is preserved when iterating
/** @type {Map<import('estree').LabeledStatement, ReactiveStatement>} */
const reactive_declarations = new Map();
/**
*
* @param {import('estree').LabeledStatement} node
* @param {ReactiveStatement} declaration
* @returns
*/
const add_declaration = (node, declaration) => {
if ([...reactive_declarations.values()].includes(declaration)) return;
for (const binding of declaration.dependencies) {
if (declaration.assignments.has(binding)) continue;
for (const [node, earlier] of lookup.get(binding.node.name) ?? []) {
add_declaration(node, earlier);
}
}
reactive_declarations.set(node, declaration);
};
for (const [node, declaration] of unsorted_reactive_declarations) {
add_declaration(node, declaration);
}
return reactive_declarations;
}