[docs] Support demos with side effect imports (mui#35177)

docs/packages/markdown/extractImports.js

@@ -1,4 +1,5 @@
-const importModuleRegexp = /^import [^'"]* from ['"]([^'"\n ][^'"\n ]*)['"]/gm;
+const importModuleRegexp =
+  /^\s*import (?:["'\s]*(?:[\w*{}\n, ]+)from\s*)?["'\s]*([^"'{}$\s]+)["'\s].*/gm;
 
 function extractImports(code) {
   return (code.match(importModuleRegexp) || []).map((x) => x.replace(importModuleRegexp, '$1'));

docs/packages/markdown/extractImports.test.js

@@ -0,0 +1,39 @@
+import { expect } from 'chai';
+import extractImports from './extractImports';
+
+describe('extractImports', () => {
+  it('finds all imports', () => {
+    const imports = extractImports(`
+import {
+  Component
+} from '@angular2/core';
+import defaultMember from "module-1";
+import   *    as name from "module-2  ";
+import   {  member }   from "  module-3";
+import { member as alias } from "module-4";
+import { member1 ,
+member2 } from "module-5";
+import { member1 , member2 as alias2 , member3 as alias3 } from "module-6";
+import defaultMember, { member, member } from "module-7";
+import defaultMember, * as name from "module-8";
+import "module-9";
+    import "module-10";
+import * from './smdn';
+import \${importName} from 'module11/\${importName}';
+  `);
+
+    expect(imports[0]).to.equal('@angular2/core');
+    expect(imports[1]).to.equal('module-1');
+    expect(imports[2]).to.equal('module-2');
+    expect(imports[3]).to.equal('module-3');
+    expect(imports[4]).to.equal('module-4');
+    expect(imports[5]).to.equal('module-5');
+    expect(imports[6]).to.equal('module-6');
+    expect(imports[7]).to.equal('module-7');
+    expect(imports[8]).to.equal('module-8');
+    expect(imports[9]).to.equal('module-9');
+    expect(imports[10]).to.equal('module-10');
+    expect(imports[11]).to.equal('./smdn');
+    expect(imports[12]).to.equal(undefined); // It's not a valid import
+  });
+});