feat(compiler): preserve whitespace in pre tag, add tests

packages/compiler-dom/__tests__/parse.spec.ts

@@ -98,6 +98,15 @@ describe('DOM parser', () => {
         }
       })
     })
+
+    test('<pre> tag should preserve raw whitespace', () => {
+      const rawText = `  \na    b    \n   c`
+      const ast = parse(`<pre>${rawText}</pre>`, parserOptions)
+      expect((ast.children[0] as ElementNode).children[0]).toMatchObject({
+        type: NodeTypes.TEXT,
+        content: rawText
+      })
+    })
   })
 
   describe('Interpolation', () => {

packages/compiler-dom/src/parserOptionsMinimal.ts

@@ -15,8 +15,8 @@ export const enum DOMNamespaces {
 
 export const parserOptionsMinimal: ParserOptions = {
   isVoidTag,
-
   isNativeTag: tag => isHTMLTag(tag) || isSVGTag(tag),
+  isPreTag: tag => tag === 'pre',
 
   // https://html.spec.whatwg.org/multipage/parsing.html#tree-construction-dispatcher
   getNamespace(tag: string, parent: ElementNode | undefined): DOMNamespaces {