Revert "use object.assign more"

This reverts commit 659e557.

utils/parse.js

@@ -1,4 +1,4 @@
-'use strict'
+"use strict"
 exports.__esModule = true
 
 const moduleRequire = require('./module-require').default
@@ -16,31 +16,29 @@ exports.default = function parse(path, content, context) {
   if (!parserPath) throw new Error('parserPath is required!')
 
   // hack: espree blows up with frozen options
-  parserOptions = Object.assign({}, parserOptions, {
-    ecmaFeatures: Object.assign({}, parserOptions.ecmaFeatures),
-
-    // always include comments and tokens (for doc parsing)
-    comment: true,
-    attachComment: true,  // keeping this for backward-compat with  older parsers
-    tokens: true,
-
-    // attach node locations
-    loc: true,
-    range: true,
-
-    // provide the `filePath` like eslint itself does, in `parserOptions`
-    // https://github.com/eslint/eslint/blob/3ec436ee/lib/linter.js#L637
-    filePath: path,
-
-    // @typescript-eslint/parser will parse the entire project with typechecking if you provide
-    // "project" or "projects" in parserOptions. Removing these options means the parser will
-    // only parse one file in isolate mode, which is much, much faster.
-    // https://github.com/benmosher/eslint-plugin-import/issues/1408#issuecomment-509298962
-    project: undefined,
-    projects: undefined,
-  })
-
-
+  parserOptions = Object.assign({}, parserOptions)
+  parserOptions.ecmaFeatures = Object.assign({}, parserOptions.ecmaFeatures)
+
+  // always include comments and tokens (for doc parsing)
+  parserOptions.comment = true
+  parserOptions.attachComment = true  // keeping this for backward-compat with  older parsers
+  parserOptions.tokens = true
+
+  // attach node locations
+  parserOptions.loc = true
+  parserOptions.range = true
+
+  // provide the `filePath` like eslint itself does, in `parserOptions`
+  // https://github.com/eslint/eslint/blob/3ec436ee/lib/linter.js#L637
+  parserOptions.filePath = path
+
+  // @typescript-eslint/parser will parse the entire project with typechecking if you provide
+  // "project" or "projects" in parserOptions. Removing these options means the parser will
+  // only parse one file in isolate mode, which is much, much faster.
+  // https://github.com/benmosher/eslint-plugin-import/issues/1408#issuecomment-509298962
+  delete parserOptions.project;
+  delete parserOptions.projects;
+
   // require the parser relative to the main module (i.e., ESLint)
   const parser = moduleRequire(parserPath)