[feat] add enableSourcemap option (#6835)

site/content/docs/04-compile-time.md

@@ -82,6 +82,8 @@ The following options can be passed to the compiler. None are required:
 | `loopGuardTimeout` | 0 | A `number` that tells Svelte to break the loop if it blocks the thread for more than `loopGuardTimeout` ms. This is useful to prevent infinite loops. **Only available when `dev: true`**
 | `preserveComments` | `false` | If `true`, your HTML comments will be preserved during server-side rendering. By default, they are stripped out.
 | `preserveWhitespace` | `false` | If `true`, whitespace inside and between elements is kept as you typed it, rather than removed or collapsed to a single space where possible.
+| `sourcemap` | `object | string` | An initial sourcemap that will be merged into the final output sourcemap. This is usually the preprocessor sourcemap.
+| `enableSourcemap` | `boolean | { js: boolean; css: boolean; }` | If `true`, Svelte generate sourcemaps for components. Use an object with `js` or `css` for more granular control of sourcemap generation. By default, this is `true`.
 | `outputFilename` | `null` | A `string` used for your JavaScript sourcemap.
 | `cssOutputFilename` | `null` | A `string` used for your CSS sourcemap.
 | `sveltePath` | `"svelte"` | The location of the `svelte` package. Any imports from `svelte` or `svelte/[module]` will be modified accordingly.

src/compiler/compile/Component.ts

@@ -36,6 +36,7 @@ import { clone } from '../utils/clone';
 import compiler_warnings from './compiler_warnings';
 import compiler_errors from './compiler_errors';
 import { extract_ignores_above_position, extract_svelte_ignore_from_comments } from '../utils/extract_svelte_ignore';
+import check_enable_sourcemap from './utils/check_enable_sourcemap';
 
 interface ComponentOptions {
 	namespace?: string;
@@ -343,21 +344,28 @@ export default class Component {
 				? { code: null, map: null }
 				: result.css;
 
-			const sourcemap_source_filename = get_sourcemap_source_filename(compile_options);
+			const js_sourcemap_enabled = check_enable_sourcemap(compile_options.enableSourcemap, 'js');
 
-			js = print(program, {
-				sourceMapSource: sourcemap_source_filename
-			});
+			if (!js_sourcemap_enabled) {
+				js = print(program);
+				js.map = null;
+			} else {
+				const sourcemap_source_filename = get_sourcemap_source_filename(compile_options);
 
-			js.map.sources = [
-				sourcemap_source_filename
-			];
+				js = print(program, {
+					sourceMapSource: sourcemap_source_filename
+				});
 
-			js.map.sourcesContent = [
-				this.source
-			];
+				js.map.sources = [
+					sourcemap_source_filename
+				];
 
-			js.map = apply_preprocessor_sourcemap(sourcemap_source_filename, js.map, compile_options.sourcemap as (string | RawSourceMap | DecodedSourceMap));
+				js.map.sourcesContent = [
+					this.source
+				];
+
+				js.map = apply_preprocessor_sourcemap(sourcemap_source_filename, js.map, compile_options.sourcemap as (string | RawSourceMap | DecodedSourceMap));
+			}
 		}
 
 		return {

src/compiler/compile/index.ts

@@ -13,6 +13,7 @@ const valid_options = [
 	'name',
 	'filename',
 	'sourcemap',
+	'enableSourcemap',
 	'generate',
 	'errorMode',
 	'varsReport',
@@ -82,7 +83,7 @@ function validate_options(options: CompileOptions, warnings: Warning[]) {
 }
 
 export default function compile(source: string, options: CompileOptions = {}) {
-	options = Object.assign({ generate: 'dom', dev: false }, options);
+	options = Object.assign({ generate: 'dom', dev: false, enableSourcemap: true }, options);
 
 	const stats = new Stats();
 	const warnings = [];

src/compiler/compile/render_dom/index.ts

@@ -10,6 +10,7 @@ import { ImportDeclaration, ClassDeclaration, FunctionExpression, Node, Statemen
 import { apply_preprocessor_sourcemap } from '../../utils/mapped_code';
 import { RawSourceMap, DecodedSourceMap } from '@ampproject/remapping/dist/types/types';
 import { flatten } from '../../utils/flatten';
+import check_enable_sourcemap from '../utils/check_enable_sourcemap';
 
 export default function dom(
 	component: Component,
@@ -34,9 +35,15 @@ export default function dom(
 
 	const css = component.stylesheet.render(options.filename, !options.customElement);
 
-	css.map = apply_preprocessor_sourcemap(options.filename, css.map, options.sourcemap as string | RawSourceMap | DecodedSourceMap);
+	const css_sourcemap_enabled = check_enable_sourcemap(options.enableSourcemap, 'css');
 
-	const styles = component.stylesheet.has_styles && options.dev
+	if (css_sourcemap_enabled) {
+		css.map = apply_preprocessor_sourcemap(options.filename, css.map, options.sourcemap as string | RawSourceMap | DecodedSourceMap);
+	} else {
+		css.map = null;
+	}
+
+	const styles = css_sourcemap_enabled && component.stylesheet.has_styles && options.dev
 		? `${css.code}\n/*# sourceMappingURL=${css.map.toUrl()} */`
 		: css.code;
 
@@ -521,7 +528,7 @@ export default function dom(
 				constructor(options) {
 					super();
 
-					${css.code && b`this.shadowRoot.innerHTML = \`<style>${css.code.replace(/\\/g, '\\\\')}${options.dev ? `\n/*# sourceMappingURL=${css.map.toUrl()} */` : ''}</style>\`;`}
+					${css.code && b`this.shadowRoot.innerHTML = \`<style>${css.code.replace(/\\/g, '\\\\')}${css_sourcemap_enabled && options.dev ? `\n/*# sourceMappingURL=${css.map.toUrl()} */` : ''}</style>\`;`}
 
 					@init(this, { target: this.shadowRoot, props: ${init_props}, customElement: true }, ${definition}, ${has_create_fragment ? 'create_fragment' : 'null'}, ${not_equal}, ${prop_indexes}, null, ${dirty});
 

src/compiler/compile/render_ssr/index.ts

@@ -10,6 +10,7 @@ import { extract_names } from 'periscopic';
 import { walk } from 'estree-walker';
 
 import { invalidate } from '../render_dom/invalidate';
+import check_enable_sourcemap from '../utils/check_enable_sourcemap';
 
 export default function ssr(
 	component: Component,
@@ -200,11 +201,13 @@ export default function ssr(
 		main
 	].filter(Boolean);
 
+	const css_sourcemap_enabled = check_enable_sourcemap(options.enableSourcemap, 'css');
+
 	const js = b`
 		${css.code ? b`
 		const #css = {
 			code: "${css.code}",
-			map: ${css.map ? string_literal(css.map.toString()) : 'null'}
+			map: ${css_sourcemap_enabled && css.map ? string_literal(css.map.toString()) : 'null'}
 		};` : null}
 
 		${component.extract_javascript(component.ast.module)}

src/compiler/compile/utils/check_enable_sourcemap.ts

@@ -0,0 +1,10 @@
+import { EnableSourcemap } from '../../interfaces';
+
+export default function check_enable_sourcemap(
+  enable_sourcemap: EnableSourcemap,
+  namespace: keyof Extract<EnableSourcemap, object>
+) {
+  return typeof enable_sourcemap === 'boolean'
+    ? enable_sourcemap
+    : enable_sourcemap[namespace];
+}

src/compiler/interfaces.ts

@@ -131,6 +131,8 @@ export interface Warning {
 
 export type ModuleFormat = 'esm' | 'cjs';
 
+export type EnableSourcemap = boolean | { js: boolean; css: boolean };
+
 export type CssHashGetter = (args: {
 	name: string;
 	filename: string | undefined;
@@ -147,6 +149,7 @@ export interface CompileOptions {
 	varsReport?: 'full' | 'strict' | false;
 
 	sourcemap?: object | string;
+	enableSourcemap?: EnableSourcemap;
 	outputFilename?: string;
 	cssOutputFilename?: string;
 	sveltePath?: string;

test/sourcemaps/index.ts

@@ -85,11 +85,13 @@ describe('sourcemaps', () => {
 				);
 			}
 
-			assert.deepEqual(
-				js.map.sources.slice().sort(),
-				(config.js_map_sources || ['input.svelte']).sort(),
-				'js.map.sources is wrong'
-			);
+			if (js.map) {
+				assert.deepEqual(
+					js.map.sources.slice().sort(),
+					(config.js_map_sources || ['input.svelte']).sort(),
+					'js.map.sources is wrong'
+				);
+			}
 			if (css.map) {
 				assert.deepEqual(
 					css.map.sources.slice().sort(),

test/sourcemaps/samples/no-sourcemap/_config.js

@@ -0,0 +1,5 @@
+export default {
+  compile_options: {
+    enableSourcemap: false
+  }
+};

test/sourcemaps/samples/no-sourcemap/input.svelte

@@ -0,0 +1,11 @@
+<script>
+	export let foo;
+</script>
+
+<p>{foo}</p>
+
+<style>
+	p {
+		color: red;
+	}
+</style>

test/sourcemaps/samples/no-sourcemap/test.js

@@ -0,0 +1,4 @@
+export function test({ assert, js, css }) {
+	assert.equal(js.map, null);
+	assert.equal(css.map, null);
+}

test/sourcemaps/samples/only-css-sourcemap/_config.js

@@ -0,0 +1,5 @@
+export default {
+  compile_options: {
+    enableSourcemap: { css: true }
+  }
+};

test/sourcemaps/samples/only-css-sourcemap/input.svelte

@@ -0,0 +1,11 @@
+<script>
+	export let foo;
+</script>
+
+<p>{foo}</p>
+
+<style>
+	p {
+		color: red;
+	}
+</style>

test/sourcemaps/samples/only-css-sourcemap/test.js

@@ -0,0 +1,4 @@
+export function test({ assert, js, css }) {
+	assert.equal(js.map, null);
+	assert.notEqual(css.map, null);
+}

test/sourcemaps/samples/only-js-sourcemap/_config.js

@@ -0,0 +1,5 @@
+export default {
+  compile_options: {
+    enableSourcemap: { js: true }
+  }
+};

test/sourcemaps/samples/only-js-sourcemap/input.svelte

@@ -0,0 +1,11 @@
+<script>
+	export let foo;
+</script>
+
+<p>{foo}</p>
+
+<style>
+	p {
+		color: red;
+	}
+</style>

test/sourcemaps/samples/only-js-sourcemap/test.js

@@ -0,0 +1,4 @@
+export function test({ assert, js, css }) {
+	assert.notEqual(js.map, null);
+	assert.equal(css.map, null);
+}