chore: dedupe getLocator calls (#11600)

...by introducing global compiler state that is reset between iterations

Author: Rich-Harris

packages/svelte/scripts/process-messages/templates/compile-warnings.js

@@ -1,29 +1,7 @@
-import { getLocator } from 'locate-character';
+import { filename, locator, warnings } from './state.js';
 
 /** @typedef {{ start?: number, end?: number }} NodeLike */
 
-/** @type {import('#compiler').Warning[]} */
-let warnings = [];
-
-/** @type {string | undefined} */
-let filename;
-
-let locator = getLocator('', { offsetLine: 1 });
-
-/**
- * @param {{
- *   source: string;
- *   filename: string | undefined;
- * }} options
- * @returns {import('#compiler').Warning[]}
- */
-export function reset_warnings(options) {
-	filename = options.filename;
-	locator = getLocator(options.source, { offsetLine: 1 });
-
-	return (warnings = []);
-}
-
 /**
  * @param {null | NodeLike} node
  * @param {string} code

packages/svelte/src/compiler/index.js

@@ -1,4 +1,3 @@
-import { getLocator } from 'locate-character';
 import { walk as zimmerframe_walk } from 'zimmerframe';
 import { CompileError } from './errors.js';
 import { convert } from './legacy.js';
@@ -8,7 +7,7 @@ import { remove_typescript_nodes } from './phases/1-parse/remove_typescript_node
 import { analyze_component, analyze_module } from './phases/2-analyze/index.js';
 import { transform_component, transform_module } from './phases/3-transform/index.js';
 import { validate_component_options, validate_module_options } from './validate-options.js';
-import { reset_warnings } from './warnings.js';
+import * as state from './state.js';
 export { default as preprocess } from './preprocess/index.js';
 
 /**
@@ -21,7 +20,8 @@ export { default as preprocess } from './preprocess/index.js';
  */
 export function compile(source, options) {
 	try {
-		const warnings = reset_warnings({ source, filename: options.filename });
+		state.reset({ source, filename: options.filename });
+
 		const validated = validate_component_options(options, '');
 		let parsed = _parse(source);
 
@@ -44,9 +44,7 @@ export function compile(source, options) {
 		}
 
 		const analysis = analyze_component(parsed, source, combined_options);
-
 		const result = transform_component(analysis, source, combined_options);
-		result.warnings = warnings;
 		result.ast = to_public_ast(source, parsed, options.modernAst);
 		return result;
 	} catch (e) {
@@ -68,11 +66,11 @@ export function compile(source, options) {
  */
 export function compileModule(source, options) {
 	try {
-		const warnings = reset_warnings({ source, filename: options.filename });
+		state.reset({ source, filename: options.filename });
+
 		const validated = validate_module_options(options, '');
 		const analysis = analyze_module(parse_acorn(source, false), validated);
 		const result = transform_module(analysis, source, validated);
-		result.warnings = warnings;
 		return result;
 	} catch (e) {
 		if (e instanceof CompileError) {
@@ -92,10 +90,8 @@ function handle_compile_error(error, filename, source) {
 	error.filename = filename;
 
 	if (error.position) {
-		// TODO this is reused with warnings — DRY out
-		const locator = getLocator(source, { offsetLine: 1 });
-		const start = locator(error.position[0]);
-		const end = locator(error.position[1]);
+		const start = state.locator(error.position[0]);
+		const end = state.locator(error.position[1]);
 
 		error.start = start;
 		error.end = end;
@@ -142,6 +138,8 @@ function handle_compile_error(error, filename, source) {
  * @returns {import('#compiler').Root | import('./types/legacy-nodes.js').LegacyRoot}
  */
 export function parse(source, options = {}) {
+	state.reset({ source, filename: options.filename });
+
 	/** @type {import('#compiler').Root} */
 	let ast;
 	try {

packages/svelte/src/compiler/migrate/index.js

@@ -4,7 +4,7 @@ import { parse } from '../phases/1-parse/index.js';
 import { analyze_component } from '../phases/2-analyze/index.js';
 import { validate_component_options } from '../validate-options.js';
 import { get_rune } from '../phases/scope.js';
-import { reset_warnings } from '../warnings.js';
+import { reset } from '../state.js';
 import { extract_identifiers } from '../utils/ast.js';
 import { regex_is_valid_identifier } from '../phases/patterns.js';
 
@@ -17,7 +17,7 @@ import { regex_is_valid_identifier } from '../phases/patterns.js';
  */
 export function migrate(source) {
 	try {
-		reset_warnings({ source, filename: 'migrate.svelte' });
+		reset({ source, filename: 'migrate.svelte' });
 
 		let parsed = parse(source);
 

packages/svelte/src/compiler/phases/1-parse/index.js

@@ -7,7 +7,7 @@ import full_char_code_at from './utils/full_char_code_at.js';
 import * as e from '../../errors.js';
 import { create_fragment } from './utils/create.js';
 import read_options from './read/options.js';
-import { getLocator } from 'locate-character';
+import { locator } from '../../state.js';
 
 const regex_position_indicator = / \(\d+:\d+\)$/;
 
@@ -42,16 +42,13 @@ export class Parser {
 	/** @type {LastAutoClosedTag | undefined} */
 	last_auto_closed_tag;
 
-	locate;
-
 	/** @param {string} template */
 	constructor(template) {
 		if (typeof template !== 'string') {
 			throw new TypeError('Template must be a string');
 		}
 
 		this.template = template.trimEnd();
-		this.locate = getLocator(this.template, { offsetLine: 1 });
 
 		let match_lang;
 
@@ -137,18 +134,6 @@ export class Parser {
 		}
 	}
 
-	/**
-	 * offset -> line/column
-	 * @param {number} start
-	 * @param {number} end
-	 */
-	get_location(start, end) {
-		return {
-			start: /** @type {import('locate-character').Location_1} */ (this.locate(start)),
-			end: /** @type {import('locate-character').Location_1} */ (this.locate(end))
-		};
-	}
-
 	current() {
 		return this.stack[this.stack.length - 1];
 	}

packages/svelte/src/compiler/phases/1-parse/read/context.js

@@ -10,6 +10,7 @@ import {
 import { parse_expression_at } from '../acorn.js';
 import { regex_not_newline_characters } from '../../patterns.js';
 import * as e from '../../../errors.js';
+import { locator } from '../../../state.js';
 
 /**
  * @param {import('../index.js').Parser} parser
@@ -29,7 +30,10 @@ export default function read_pattern(parser, optional_allowed = false) {
 			type: 'Identifier',
 			name,
 			start,
-			loc: parser.get_location(start, parser.index),
+			loc: {
+				start: /** @type {import('locate-character').Location} */ (locator(start)),
+				end: /** @type {import('locate-character').Location} */ (locator(parser.index))
+			},
 			end: parser.index,
 			typeAnnotation: annotation
 		};

packages/svelte/src/compiler/phases/3-transform/client/transform-client.js

@@ -8,7 +8,6 @@ import { javascript_visitors_runes } from './visitors/javascript-runes.js';
 import { javascript_visitors_legacy } from './visitors/javascript-legacy.js';
 import { serialize_get_binding } from './utils.js';
 import { render_stylesheet } from '../css/index.js';
-import { getLocator } from 'locate-character';
 
 /**
  * This function ensures visitor sets don't accidentally clobber each other
@@ -48,7 +47,6 @@ export function client_component(source, analysis, options) {
 		scopes: analysis.template.scopes,
 		hoisted: [b.import_all('$', 'svelte/internal/client')],
 		node: /** @type {any} */ (null), // populated by the root node
-		source_locator: getLocator(source, { offsetLine: 1 }),
 		// these should be set by create_block - if they're called outside, it's a bug
 		get before_init() {
 			/** @type {any[]} */

packages/svelte/src/compiler/phases/3-transform/client/types.d.ts

@@ -33,10 +33,6 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	readonly options: ValidatedCompileOptions;
 	readonly hoisted: Array<Statement | ModuleDeclaration>;
 	readonly events: Set<string>;
-	readonly source_locator: (
-		search: string | number,
-		index?: number | undefined
-	) => Location | undefined;
 
 	/** Stuff that happens before the render effect(s) */
 	readonly before_init: Statement[];

packages/svelte/src/compiler/phases/3-transform/client/visitors/template.js

@@ -38,6 +38,7 @@ import { regex_is_valid_identifier } from '../../../patterns.js';
 import { javascript_visitors_runes } from './javascript-runes.js';
 import { sanitize_template_string } from '../../../../utils/sanitize_template_string.js';
 import { walk } from 'zimmerframe';
+import { locator } from '../../../../state.js';
 
 /**
  * @param {import('#compiler').RegularElement | import('#compiler').SvelteElement} element
@@ -1841,7 +1842,7 @@ export const template_visitors = {
 		let location = [-1, -1];
 
 		if (context.state.options.dev) {
-			const loc = context.state.source_locator(node.start);
+			const loc = locator(node.start);
 			if (loc) {
 				location[0] = loc.line;
 				location[1] = loc.column;
@@ -2192,7 +2193,7 @@ export const template_visitors = {
 			})
 		);
 
-		const location = context.state.options.dev && context.state.source_locator(node.start);
+		const location = context.state.options.dev && locator(node.start);
 
 		context.state.init.push(
 			b.stmt(

packages/svelte/src/compiler/phases/3-transform/index.js

@@ -2,9 +2,9 @@ import { print } from 'esrap';
 import { VERSION } from '../../../version.js';
 import { server_component, server_module } from './server/transform-server.js';
 import { client_component, client_module } from './client/transform-client.js';
-import { getLocator } from 'locate-character';
 import { render_stylesheet } from './css/index.js';
 import { merge_with_preprocessor_map, get_source_name } from '../../utils/mapped_code.js';
+import * as state from '../../state.js';
 
 /**
  * @param {import('../types').ComponentAnalysis} analysis
@@ -17,7 +17,7 @@ export function transform_component(analysis, source, options) {
 		return {
 			js: /** @type {any} */ (null),
 			css: null,
-			warnings: /** @type {any} */ (null), // set afterwards
+			warnings: state.warnings, // set afterwards
 			metadata: {
 				runes: analysis.runes
 			},
@@ -46,7 +46,7 @@ export function transform_component(analysis, source, options) {
 	return {
 		js,
 		css,
-		warnings: /** @type {any} */ (null), // set afterwards. TODO apply preprocessor sourcemap
+		warnings: state.warnings, // set afterwards. TODO apply preprocessor sourcemap
 		metadata: {
 			runes: analysis.runes
 		},
@@ -65,7 +65,7 @@ export function transform_module(analysis, source, options) {
 		return {
 			js: /** @type {any} */ (null),
 			css: null,
-			warnings: /** @type {any} */ (null), // set afterwards
+			warnings: state.warnings, // set afterwards
 			metadata: {
 				runes: true
 			},
@@ -94,7 +94,7 @@ export function transform_module(analysis, source, options) {
 		metadata: {
 			runes: true
 		},
-		warnings: /** @type {any} */ (null), // set afterwards
+		warnings: state.warnings, // set afterwards
 		ast: /** @type {any} */ (null) // set afterwards
 	};
 }

packages/svelte/src/compiler/state.js

@@ -0,0 +1,23 @@
+import { getLocator } from 'locate-character';
+
+/** @typedef {{ start?: number, end?: number }} NodeLike */
+
+/** @type {import('#compiler').Warning[]} */
+export let warnings = [];
+
+/** @type {string | undefined} */
+export let filename;
+
+export let locator = getLocator('', { offsetLine: 1 });
+
+/**
+ * @param {{
+ *   source: string;
+ *   filename: string | undefined;
+ * }} options
+ */
+export function reset(options) {
+	filename = options.filename;
+	locator = getLocator(options.source, { offsetLine: 1 });
+	warnings = [];
+}