Update custom template documentation, extend template package blacklist (#8082)

Author: tomvalorsa

docusaurus/docs/custom-templates.md

@@ -58,28 +58,31 @@ You can add whatever files you want in here, but you must have at least the file
 
 ### The `template.json` file
 
-This is the configuration file for your template. It allows you to define information that should become a part of the generated project's `package.json` file, such as dependencies (only dependencies are supported for now) and any custom scripts that your template relies on. It should be structured as follows:
+This is the configuration file for your template. As this is a new feature, more options will be added over time. For now, only a `package` key is supported.
+
+The `package` key lets you provide any keys/values that you want added to the new project's `package.json`, such as dependencies (only dependencies are supported for now) and any custom scripts that your template relies on.
+
+Below is an example `template.json` file:
 
 ```json
 {
   "package": {
     "dependencies": {
+      "eslint-plugin-jsx-a11y": "^6.2.3",
       "serve": "^11.2.0"
     },
     "scripts": {
       "serve": "serve -s build",
       "build-and-serve": "npm run build && npm run serve"
     },
-    "browserslist": [
-      "defaults",
-      "not IE 11",
-      "not IE_Mob 11",
-      "maintained node versions",
-    ]
+    "eslintConfig": {
+      "extends": ["react-app", "plugin:jsx-a11y/recommended"],
+      "plugins": ["jsx-a11y"]
+    }
   }
 }
 ```
 
-Any values you add for `"dependencies"` and `"scripts"` will be merged with the values used in the initialisation process of `react-scripts`. Any other information you add to `"package"` will be added to the generated project's `package.json` file, replacing any existing values associated with those keys.
+Any values you add for `"dependencies"` and `"scripts"` will be merged with the Create React App defaults. Values for any other keys will be used as-is, replacing any matching Create React App defaults.
 
 For convenience, we always replace `npm run` with `yarn` in your custom `"scripts"`, as well as in your `README` when projects are initialized with yarn.

packages/react-scripts/scripts/init.js

@@ -122,26 +122,45 @@ module.exports = function(
 
   // Keys to ignore in templatePackage
   const templatePackageBlacklist = [
+    'name',
+    'version',
+    'description',
+    'keywords',
+    'homepage',
+    'bugs',
+    'license',
+    'author',
+    'contributors',
+    'files',
+    'main',
+    'browser',
+    'bin',
+    'man',
+    'directories',
+    'repository',
     'devDependencies',
     'peerDependencies',
-    'name',
+    'bundledDependencies',
+    'optionalDependencies',
+    'engineStrict',
+    'os',
+    'cpu',
+    'preferGlobal',
+    'private',
+    'publishConfig',
   ];
 
   // Keys from templatePackage that will be merged with appPackage
-  const templatePackageToMerge = [
-    'dependencies',
-    'scripts',
-  ];
+  const templatePackageToMerge = ['dependencies', 'scripts'];
 
   // Keys from templatePackage that will be added to appPackage,
   // replacing any existing entries.
-  const templatePackageToReplace = Object.keys(templatePackage)
-    .filter(key => {
-      return (
-        templatePackageBlacklist.indexOf(key) === -1 &&
-        templatePackageToMerge.indexOf(key) === -1
-      );
-    });
+  const templatePackageToReplace = Object.keys(templatePackage).filter(key => {
+    return (
+      templatePackageBlacklist.indexOf(key) === -1 &&
+      templatePackageToMerge.indexOf(key) === -1
+    );
+  });
 
   // Copy over some of the devDependencies
   appPackage.dependencies = appPackage.dependencies || {};
@@ -253,7 +272,8 @@ module.exports = function(
 
   // Install additional template dependencies, if present
   // TODO: deprecate 'dependencies' key directly on templateJson
-  const templateDependencies = templatePackage.dependencies || templateJson.dependencies;
+  const templateDependencies =
+    templatePackage.dependencies || templateJson.dependencies;
   if (templateDependencies) {
     args = args.concat(
       Object.keys(templateDependencies).map(key => {