refactor: remove vue-template-compiler from peer dep

Author: yyx990803

Diff for: lib/index.js

@@ -14,6 +14,17 @@ const { NS } = require('./plugin')
 
 let errorEmitted = false
 
+function loadTemplateCompiler () {
+  try {
+    return require('vue-template-compiler')
+  } catch (e) {
+    throw new Error(
+      `[vue-loader] vue-template-compiler must be installed as a peer dependency, ` +
+      `or a compatible compiler implementation must be passed via options.`
+    )
+  }
+}
+
 module.exports = function (source) {
   const loaderContext = this
 
@@ -51,7 +62,7 @@ module.exports = function (source) {
 
   const descriptor = parse({
     source,
-    compiler: options.compiler || require('vue-template-compiler'),
+    compiler: options.compiler || loadTemplateCompiler(),
     filename,
     sourceRoot,
     needMap: sourceMap

Diff for: package.json

@@ -33,8 +33,7 @@
     ]
   },
   "peerDependencies": {
-    "css-loader": "*",
-    "vue-template-compiler": "^2.0.0"
+    "css-loader": "*"
   },
   "dependencies": {
     "@vue/component-compiler-utils": "^2.0.0",