feat: asset handling for support vite dev.

lib/compileTemplate.ts

@@ -5,7 +5,8 @@ import {
 } from './types'
 
 import assetUrlsModule, {
-  AssetURLOptions
+  AssetURLOptions,
+  TransformAssetUrlsOptions
 } from './templateCompilerModules/assetUrl'
 import srcsetModule from './templateCompilerModules/srcset'
 
@@ -18,6 +19,7 @@ export interface TemplateCompileOptions {
   compiler: VueTemplateCompiler
   compilerOptions?: VueTemplateCompilerOptions
   transformAssetUrls?: AssetURLOptions | boolean
+  transformAssetUrlsOptions?: TransformAssetUrlsOptions
   preprocessLang?: string
   preprocessOptions?: any
   transpileOptions?: any
@@ -103,6 +105,7 @@ function actuallyCompile(
     compilerOptions = {},
     transpileOptions = {},
     transformAssetUrls,
+    transformAssetUrlsOptions,
     isProduction = process.env.NODE_ENV === 'production',
     isFunctional = false,
     optimizeSSR = false,
@@ -116,9 +119,9 @@ function actuallyCompile(
   if (transformAssetUrls) {
     const builtInModules = [
       transformAssetUrls === true
-        ? assetUrlsModule()
-        : assetUrlsModule(transformAssetUrls),
-      srcsetModule()
+        ? assetUrlsModule(undefined, transformAssetUrlsOptions)
+        : assetUrlsModule(transformAssetUrls, transformAssetUrlsOptions),
+      srcsetModule(transformAssetUrlsOptions)
     ]
     finalCompilerOptions = Object.assign({}, compilerOptions, {
       modules: [...builtInModules, ...(compilerOptions.modules || [])],

lib/templateCompilerModules/assetUrl.ts

@@ -6,6 +6,14 @@ export interface AssetURLOptions {
   [name: string]: string | string[]
 }
 
+export interface TransformAssetUrlsOptions {
+  /**
+   * If base is provided, instead of transforming relative asset urls into
+   * imports, they will be directly rewritten to absolute urls.
+   */
+  base?: string
+}
+
 const defaultOptions: AssetURLOptions = {
   audio: 'src',
   video: ['src', 'poster'],
@@ -15,37 +23,52 @@ const defaultOptions: AssetURLOptions = {
   use: ['xlink:href', 'href']
 }
 
-export default (userOptions?: AssetURLOptions) => {
+export default (
+  userOptions?: AssetURLOptions,
+  transformAssetUrlsOption?: TransformAssetUrlsOptions
+) => {
   const options = userOptions
     ? Object.assign({}, defaultOptions, userOptions)
     : defaultOptions
 
   return {
     postTransformNode: (node: ASTNode) => {
-      transform(node, options)
+      transform(node, options, transformAssetUrlsOption)
     }
   }
 }
 
-function transform(node: ASTNode, options: AssetURLOptions) {
+function transform(
+  node: ASTNode,
+  options: AssetURLOptions,
+  transformAssetUrlsOption?: TransformAssetUrlsOptions
+) {
   for (const tag in options) {
     if ((tag === '*' || node.tag === tag) && node.attrs) {
       const attributes = options[tag]
       if (typeof attributes === 'string') {
-        node.attrs.some(attr => rewrite(attr, attributes))
+        node.attrs.some(attr =>
+          rewrite(attr, attributes, transformAssetUrlsOption)
+        )
       } else if (Array.isArray(attributes)) {
-        attributes.forEach(item => node.attrs.some(attr => rewrite(attr, item)))
+        attributes.forEach(item =>
+          node.attrs.some(attr => rewrite(attr, item, transformAssetUrlsOption))
+        )
       }
     }
   }
 }
 
-function rewrite(attr: Attr, name: string) {
+function rewrite(
+  attr: Attr,
+  name: string,
+  transformAssetUrlsOption?: TransformAssetUrlsOptions
+) {
   if (attr.name === name) {
     const value = attr.value
     // only transform static URLs
     if (value.charAt(0) === '"' && value.charAt(value.length - 1) === '"') {
-      attr.value = urlToRequire(value.slice(1, -1))
+      attr.value = urlToRequire(value.slice(1, -1), transformAssetUrlsOption)
       return true
     }
   }

lib/templateCompilerModules/srcset.ts

@@ -1,22 +1,26 @@
 // vue compiler module for transforming `img:srcset` to a number of `require`s
 
 import { urlToRequire, ASTNode } from './utils'
+import { TransformAssetUrlsOptions } from './assetUrl'
 
 interface ImageCandidate {
   require: string
   descriptor: string
 }
 
-export default () => ({
+export default (transformAssetUrlsOptions?: TransformAssetUrlsOptions) => ({
   postTransformNode: (node: ASTNode) => {
-    transform(node)
+    transform(node, transformAssetUrlsOptions)
   }
 })
 
 // http://w3c.github.io/html/semantics-embedded-content.html#ref-for-image-candidate-string-5
 const escapedSpaceCharacters = /( |\\t|\\n|\\f|\\r)+/g
 
-function transform(node: ASTNode) {
+function transform(
+  node: ASTNode,
+  transformAssetUrlsOptions?: TransformAssetUrlsOptions
+) {
   const tags = ['img', 'source']
 
   if (tags.indexOf(node.tag) !== -1 && node.attrs) {
@@ -40,7 +44,10 @@ function transform(node: ASTNode) {
               .replace(escapedSpaceCharacters, ' ')
               .trim()
               .split(' ', 2)
-            return { require: urlToRequire(url), descriptor }
+            return {
+              require: urlToRequire(url, transformAssetUrlsOptions),
+              descriptor
+            }
           })
 
         // "require(url1)"

lib/templateCompilerModules/utils.ts

@@ -1,3 +1,7 @@
+import { TransformAssetUrlsOptions } from './assetUrl'
+import { UrlWithStringQuery, parse as uriParse } from 'url'
+import path from 'path'
+
 export interface Attr {
   name: string
   value: string
@@ -8,20 +12,36 @@ export interface ASTNode {
   attrs: Attr[]
 }
 
-import { UrlWithStringQuery, parse as uriParse } from 'url'
-
-export function urlToRequire(url: string): string {
+export function urlToRequire(
+  url: string,
+  transformAssetUrlsOption: TransformAssetUrlsOptions = {}
+): string {
   const returnValue = `"${url}"`
   // same logic as in transform-require.js
   const firstChar = url.charAt(0)
-  if (firstChar === '.' || firstChar === '~' || firstChar === '@') {
-    if (firstChar === '~') {
-      const secondChar = url.charAt(1)
-      url = url.slice(secondChar === '/' ? 2 : 1)
-    }
+  if (firstChar === '~') {
+    const secondChar = url.charAt(1)
+    url = url.slice(secondChar === '/' ? 2 : 1)
+  }
 
-    const uriParts = parseUriParts(url)
+  const uriParts = parseUriParts(url)
 
+  if (transformAssetUrlsOption.base) {
+    // explicit base - directly rewrite the url into absolute url
+    // does not apply to absolute urls or urls that start with `@`
+    // since they are aliases
+    if (firstChar === '.' || firstChar === '~') {
+      // when packaged in the browser, path will be using the posix-
+      // only version provided by rollup-plugin-node-builtins.
+      return `"${(path.posix || path).join(
+        transformAssetUrlsOption.base,
+        uriParts.path + (uriParts.hash || '')
+      )}"`
+    }
+    return returnValue
+  }
+
+  if (firstChar === '.' || firstChar === '~' || firstChar === '@') {
     if (!uriParts.hash) {
       return `require("${url}")`
     } else {

test/compileTemplate.spec.ts

@@ -204,3 +204,31 @@ test('transform srcset', () => {
   )
   expect(vnode.children[18].data.attrs.srcset).toBe('test-url 2x, test-url 3x')
 })
+
+test('transform assetUrls and srcset with base option', () => {
+  const source = `
+<div>
+  <img src="./logo.png">
+  <img src="~fixtures/logo.png">
+  <img src="~/fixtures/logo.png">
+  <img src="./logo.png" srcset="./logo.png 2x, ./logo.png 3x">
+</div>
+`
+  const result = compileTemplate({
+    compiler: compiler as VueTemplateCompiler,
+    filename: 'example.vue',
+    source,
+    transformAssetUrls: true,
+    transformAssetUrlsOptions: { base: '/base/' }
+  })
+
+  expect(result.errors.length).toBe(0)
+
+  const vnode = mockRender(result.code)
+  expect(vnode.children[0].data.attrs.src).toBe('/base/logo.png')
+  expect(vnode.children[2].data.attrs.src).toBe('/base/fixtures/logo.png')
+  expect(vnode.children[4].data.attrs.src).toBe('/base/fixtures/logo.png')
+  expect(vnode.children[6].data.attrs.srcset).toBe(
+    '/base/logo.png 2x, /base/logo.png 3x'
+  )
+})