Add rollup import transform

utils/rollup-build-target.mjs

@@ -11,6 +11,7 @@ import { visualizer } from 'rollup-plugin-visualizer';
 import { shaderChunks } from './rollup-shader-chunks.mjs';
 import { engineLayerImportValidation } from './rollup-import-validation.mjs';
 import { spacesToTabs } from './rollup-spaces-to-tabs.mjs';
+import { dynamicImportTransform } from './rollup-dynamic-import-transform.mjs';
 
 import { version, revision } from './rollup-version-revision.mjs';
 import { getBanner } from './rollup-get-banner.mjs';
@@ -177,6 +178,7 @@ function buildTarget(buildType, moduleFormat, input = 'src/index.js', buildDir =
         output: outputOptions,
         plugins: [
             jscc(jsccParam),
+            moduleFormat === 'es5' ? dynamicImportTransform() : undefined,
             shaderChunks({ enabled: buildType !== 'debug' }),
             engineLayerImportValidation(input, buildType === 'debug'),
             buildType !== 'debug' ? strip(stripOptions) : undefined,

utils/rollup-dynamic-import-transform.mjs

@@ -0,0 +1,25 @@
+/**
+ * This rollup plugin transform code with dynamic import statements and wraps them
+ * in a `new Function('import("modulePath")')` statement, in order to avoid parsing errors in older browsers
+ * without support for dynamic imports.
+ *
+ * Note that whilst this will prevent parsing errors, it can trigger CSP errors.
+ */
+
+export function dynamicImportTransform() {
+    return {
+        name: 'dynamic-import-transform',
+        transform(code, id) {
+            /**
+             * Transforms the code by replacing `import(` with `new Function("return import")(`.
+             * @param {string} code - The code to transform.
+             * @param {string} id - The id of the code.
+             * @returns {object} - The transformed code and map.
+             */
+            return {
+                code: code.replace(/import\(/g, 'new Function("modulePath", "return import(modulePath)")('),
+                map: null
+            };
+        }
+    };
+}