chore: refactor packageManager.js for less redundancy

package.json

@@ -28,6 +28,7 @@
     "@react-native-community/eslint-config": "^0.0.5",
     "@types/jest": "^24.0.11",
     "@types/node": "^11.13.0",
+    "@types/node-fetch": "^2.3.7",
     "babel-jest": "^24.6.0",
     "babel-plugin-module-resolver": "^3.2.0",
     "chalk": "^2.4.2",

packages/cli/src/tools/packageManager.js

@@ -11,6 +11,34 @@ type Options = {|
 
 let projectDir;
 
+const packageManagers = {
+  yarn: {
+    add: ['add'],
+    addDev: ['add', '-D'],
+    remove: ['remove'],
+    install: ['install'],
+  },
+  npm: {
+    add: ['install', '--save', '--save-exact'],
+    addDev: ['install', '--save-dev', '--save-exact'],
+    remove: ['uninstall', '--save'],
+    install: ['install'],
+  },
+};
+
+function configurePackageManager(
+  packageNames: Array<string>,
+  options?: Options,
+  action: 'add' | 'addDev' | 'remove',
+) {
+  const pm = shouldUseYarn(options) ? 'yarn' : 'npm';
+  const pmConfig = packageManagers[pm];
+
+  const [executable, ...flags] = pmConfig[action];
+  const args = [executable, ...flags, ...packageNames];
+  return executeCommand(pm, args, options);
+}
+
 function executeCommand(
   command: string,
   args: Array<string>,
@@ -36,33 +64,20 @@ export function setProjectDir(dir: string) {
 }
 
 export function install(packageNames: Array<string>, options?: Options) {
-  return shouldUseYarn(options)
-    ? executeCommand('yarn', ['add', ...packageNames], options)
-    : executeCommand(
-        'npm',
-        ['install', ...packageNames, '--save', '--save-exact'],
-        options,
-      );
+  return configurePackageManager(packageNames, options, 'add');
 }
 
 export function installDev(packageNames: Array<string>, options?: Options) {
-  return shouldUseYarn(options)
-    ? executeCommand('yarn', ['add', '-D', ...packageNames], options)
-    : executeCommand(
-        'npm',
-        ['install', ...packageNames, '--save-dev', '--save-exact'],
-        options,
-      );
+  return configurePackageManager(packageNames, options, 'addDev');
 }
 
 export function uninstall(packageNames: Array<string>, options?: Options) {
-  return shouldUseYarn(options)
-    ? executeCommand('yarn', ['remove', ...packageNames], options)
-    : executeCommand('npm', ['uninstall', ...packageNames, '--save'], options);
+  return configurePackageManager(packageNames, options, 'remove');
 }
 
 export function installAll(options?: Options) {
-  return shouldUseYarn(options)
-    ? executeCommand('yarn', ['install'], options)
-    : executeCommand('npm', ['install'], options);
+  const pm = shouldUseYarn(options) ? 'yarn' : 'npm';
+  const pmConfig = packageManagers[pm];
+
+  return executeCommand(pm, pmConfig.install, options);
 }

yarn.lock

@@ -1975,6 +1975,13 @@
   dependencies:
     "@types/node" "*"
 
+"@types/node-fetch@^2.3.7":
+  version "2.3.7"
+  resolved "https://registry.yarnpkg.com/@types/node-fetch/-/node-fetch-2.3.7.tgz#b7212e895100f8642dbdab698472bab5f3c1d2f1"
+  integrity sha512-+bKtuxhj/TYSSP1r4CZhfmyA0vm/aDRQNo7vbAgf6/cZajn0SAniGGST07yvI4Q+q169WTa2/x9gEHfJrkcALw==
+  dependencies:
+    "@types/node" "*"
+
 "@types/node@*":
   version "12.0.0"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-12.0.0.tgz#d11813b9c0ff8aaca29f04cbc12817f4c7d656e5"