Fixed resolving dependencies inside tag attributes (#16)

* Added support for block nodes

Block nodes might not have a `filename` field but instead a `nodes` field with an array of sub-nodes.
Additionally, I added a check on the `filename` field to see if it's undefined to avoid parcel from crashing during the bundling step in cases where the node would have no `filename` field.

* Update PugAsset.ts

* Fixed semicolon

* Added type declarations

* Fixed resolving dependencies inside tag attributes

* Fix side-effect bug introduced by double url resolution

* Remove unused url resolution and linked modules

* Removed unused module declaration from modules.d.ts

* Added srcset to the list of supported attributes

src/Asset/index.d.ts

@@ -4,11 +4,14 @@ export class Asset {
   parse(code: string): any;
   addDependency(path: string, options: Object): any;
   addURLDependency(url: string): string;
+  process(): Promise<any>;
 
   name: string;
   isAstDirty: boolean;
   contents: string;
   ast: any;
   options: any;
   dependencies: Set<Object>;
+  generated: any;
+  package: any;
 }

src/PugAsset.ts

@@ -1,8 +1,5 @@
-import url = require('url');
-import path = require('path');
-
 import { Asset } from './Asset';
-import isURL = require('parcel-bundler/lib/utils/is-url');
+import HTMLAsset = require('parcel-bundler/lib/assets/HTMLAsset');
 
 import load = require('pug-load');
 import lexer = require('pug-lexer');
@@ -41,10 +38,14 @@ const ATTRS: Dictionary<string[]> = {
     'iframe',
     'embed'
   ],
+  srcset: ['img'],
   href: ['link', 'a'],
   poster: ['video']
 };
 
+// A regex to detect if a variable is a 'pure' string (no evaluation needed)
+const PURE_STRING_REGEX: RegExp = /(^"([^"]+)"$)|(^'([^']+)'$)/g;
+
 export = class PugAsset extends Asset {
   public type = 'html';
 
@@ -72,11 +73,11 @@ export = class PugAsset extends Asset {
           (cNode as Block).nodes.forEach((n: any) => recursiveCollect(n));
         } else {
           if (cNode.filename && cNode.filename !== this.name && !this.dependencies.has(cNode.filename)) {
-          this.addDependency(cNode.filename, {
-            name: cNode.filename,
-            includedInParent: true,
-          });
-        }
+            this.addDependency(cNode.filename, {
+              name: cNode.filename,
+              includedInParent: true,
+            });
+          }
         }
       };
 
@@ -86,21 +87,29 @@ export = class PugAsset extends Asset {
         for (const attr of node.attrs) {
           const elements = ATTRS[attr.name];
           if (node.type === 'Tag' && elements && elements.indexOf(node.name) > -1) {
-            let assetPath = attr.val.substring(1, attr.val.length - 1);
-            assetPath = this.addURLDependency(assetPath);
-            if (!isURL(assetPath)) {
-              // Use url.resolve to normalize path for windows
-              // from \path\to\res.js to /path/to/res.js
-              assetPath = url.resolve(path.join(this.options.publicURL, assetPath), '');
+            if (PURE_STRING_REGEX.test(attr.val)) {
+              const assetPath = attr.val.substring(1, attr.val.length - 1);
+              this.addURLDependency(assetPath);
             }
-            attr.val = `'${assetPath}'`;
           }
         }
       }
       return node;
     });
   }
 
+  public async process(): Promise<any> {
+    await super.process();
+
+    const htmlAsset = new HTMLAsset(this.name, this.package, this.options);
+    htmlAsset.contents = this.generated.html;
+    await htmlAsset.process();
+
+    Object.assign(this, htmlAsset);
+
+    return this.generated;
+  }
+
   public generate() {
     const result = generateCode(this.ast, {
       compileDebug: false,

src/modules.d.ts

@@ -17,9 +17,15 @@ declare module 'parcel-bundler/lib/Asset' {
   export = Asset;
 }
 
-declare module 'parcel-bundler/lib/utils/is-url' {
-  function isURL(url: string): boolean;
-  export = isURL;
+declare module 'parcel-bundler/lib/assets/HTMLAsset' {
+  class HTMLAsset {
+    constructor(name: string, pkg: string, options: any);
+
+    process(): Promise<any>;
+
+    contents: string;
+  }
+  export = HTMLAsset;
 }
 
 declare module 'pug-load' {
@@ -64,4 +70,3 @@ declare module 'pug-filters' {
   function runFilter(name: string, str: string, options: any, currentDirectory: string, funcName: string): any;
   function handleFilters(ast: any, filters?: any): any;
 }
-