Fix sourcemaps in dev builds (#25901)

* Adds magic-string
* Improves custom Rollup plugins to preserve sourcemaps

package-lock.json

@@ -20,6 +20,7 @@
         "eslint-plugin-import": "^2.27.5",
         "failonlyreporter": "^1.0.0",
         "jimp": "^0.22.7",
+        "magic-string": "^0.30.0",
         "pixelmatch": "^5.3.0",
         "puppeteer-core": "^19.8.1",
         "qunit": "^2.19.4",
@@ -4146,6 +4147,18 @@
         "node": ">=10"
       }
     },
+    "node_modules/magic-string": {
+      "version": "0.30.0",
+      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.0.tgz",
+      "integrity": "sha512-LA+31JYDJLs82r2ScLrlz1GjSgu66ZV518eyWT+S8VhyQn/JL0u9MeBOvQMGYiPk1DBiSN9DDMOcXvigJZaViQ==",
+      "dev": true,
+      "dependencies": {
+        "@jridgewell/sourcemap-codec": "^1.4.13"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/make-fetch-happen": {
       "version": "10.2.1",
       "resolved": "https://registry.npmjs.org/make-fetch-happen/-/make-fetch-happen-10.2.1.tgz",
@@ -10241,6 +10254,15 @@
         "yallist": "^4.0.0"
       }
     },
+    "magic-string": {
+      "version": "0.30.0",
+      "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.0.tgz",
+      "integrity": "sha512-LA+31JYDJLs82r2ScLrlz1GjSgu66ZV518eyWT+S8VhyQn/JL0u9MeBOvQMGYiPk1DBiSN9DDMOcXvigJZaViQ==",
+      "dev": true,
+      "requires": {
+        "@jridgewell/sourcemap-codec": "^1.4.13"
+      }
+    },
     "make-fetch-happen": {
       "version": "10.2.1",
       "resolved": "https://registry.npmjs.org/make-fetch-happen/-/make-fetch-happen-10.2.1.tgz",

package.json

@@ -95,6 +95,7 @@
     "eslint-plugin-import": "^2.27.5",
     "failonlyreporter": "^1.0.0",
     "jimp": "^0.22.7",
+    "magic-string": "^0.30.0",
     "pixelmatch": "^5.3.0",
     "puppeteer-core": "^19.8.1",
     "qunit": "^2.19.4",

utils/build/rollup.config.js

@@ -1,4 +1,5 @@
 import terser from '@rollup/plugin-terser';
+import MagicString from 'magic-string';
 
 function addons() {
 
@@ -8,11 +9,13 @@ function addons() {
 
 			if ( /\/examples\/jsm\//.test( id ) === false ) return;
 
-			code = code.replace( 'build/three.module.js', 'src/Three.js' );
+			code = new MagicString( code );
+
+			code.replace( 'build/three.module.js', 'src/Three.js' );
 
 			return {
-				code: code,
-				map: null
+				code: code.toString(),
+				map: code.generateMap().toString()
 			};
 
 		}
@@ -29,7 +32,9 @@ export function glsl() {
 
 			if ( /\.glsl.js$/.test( id ) === false ) return;
 
-			code = code.replace( /\/\* glsl \*\/\`(.*?)\`/sg, function ( match, p1 ) {
+			code = new MagicString( code );
+
+			code.replace( /\/\* glsl \*\/\`(.*?)\`/sg, function ( match, p1 ) {
 
 				return JSON.stringify(
 					p1
@@ -43,8 +48,8 @@ export function glsl() {
 			} );
 
 			return {
-				code: code,
-				map: null
+				code: code.toString(),
+				map: code.generateMap().toString()
 			};
 
 		}
@@ -59,12 +64,18 @@ function header() {
 
 		renderChunk( code ) {
 
-			return `/**
+			code = new MagicString( code );
+
+			code.prepend( `/**
  * @license
  * Copyright 2010-2023 Three.js Authors
  * SPDX-License-Identifier: MIT
- */
-${ code }`;
+ */\n` );
+
+			return {
+				code: code.toString(),
+				map: code.generateMap().toString()
+			};
 
 		}
 
@@ -78,8 +89,14 @@ function deprecationWarning() {
 
 		renderChunk( code ) {
 
-			return `console.warn( 'Scripts "build/three.js" and "build/three.min.js" are deprecated with r150+, and will be removed with r160. Please use ES Modules or alternatives: https://threejs.org/docs/index.html#manual/en/introduction/Installation' );
-${ code }`;
+			code = new MagicString( code );
+
+			code.prepend( `console.warn( 'Scripts "build/three.js" and "build/three.min.js" are deprecated with r150+, and will be removed with r160. Please use ES Modules or alternatives: https://threejs.org/docs/index.html#manual/en/introduction/Installation' );\n` );
+
+			return {
+				code: code.toString(),
+				map: code.generateMap().toString()
+			};
 
 		}