fix: 修正postcss-loader 的插入位置;

Author: liuqi

lib/core/loader.js

@@ -262,7 +262,8 @@ module.exports = {
           }
         });
         if (this.postcss && itemLoader.postcss) {
-          const postcssIndex = ['css', 'css_module'].includes(name) ? itemLoader.use.length : itemLoader.use.length - 1;
+          const cssIndex = this.utils.getLoaderIndex(itemLoader.use, 'css-loader');
+          const postcssIndex = cssIndex ? cssIndex : this.utils.getLoaderIndex(itemLoader.use, 'style-loader');
           const postcssLoader = this.createPostCssLoader(loaderOptions && loaderOptions.postcss);
           itemLoader.use.splice(postcssIndex, 0, postcssLoader);
         }

utils/utils.js

@@ -81,6 +81,10 @@ utils.joinPath = function() {
   }).join('/');
 };
 
+utils.getLoaderIndex = (loaders, loaderName) => {
+  return loaders.findIndex(loader => loaderName === (utils.isObject(loader) ? loader.loader : loader)) + 1;
+}
+
 utils.getOutputPath = config => {
   const { output = {}, buildPath } = config;
   if (output.path) {