add npm check to babel-doctor

packages/babel-cli/package.json

@@ -11,6 +11,7 @@
     "babel-core": "^6.0.15",
     "babel-polyfill": "^6.0.14",
     "babel-runtime": "^5.0.0",
+    "bin-version-check": "^2.1.0",
     "chalk": "1.1.1",
     "chokidar": "^1.0.0",
     "commander": "^2.8.1",

packages/babel-cli/src/babel-doctor/index.js

@@ -42,11 +42,13 @@ while (nodeModulesDirectories.length) {
     if (packageName[0] === ".") continue;
 
     let packageLoc = path.join(loc, packageName);
+    let packageJsonLoc = path.join(packageLoc, "package.json");
+    if (!fs.existsSync(packageJsonLoc)) continue;
 
     packages.push({
       name: packageName,
       loc: packageLoc,
-      version: require(path.join(packageLoc, "package.json")).version
+      version: require(packageJsonLoc).version
     });
 
     nodeModulesDirectories.push(path.join(packageLoc, "node_modules"));

packages/babel-cli/src/babel-doctor/rules/index.js

@@ -1,3 +1,4 @@
 export { default as hasConfig } from "./has-config";
 export { default as deduped } from "./deduped";
 export { default as latestPackages } from "./latest-packages";
+export { default as npm } from "./npm-3";

packages/babel-cli/src/babel-doctor/rules/npm-3.js

@@ -0,0 +1,14 @@
+import binVersionCheck from "bin-version-check";
+import chalk from "chalk";
+
+export default function () {
+  return new Promise(function (resolve) {
+    binVersionCheck("npm", ">=3.3.0", function (err) {
+      if (err) {
+        resolve([false, `Your npm version is outdated. Upgrade to the latest version by running:\n$ ${chalk.magenta("npm install -g npm")}`]);
+      } else {
+        resolve([true, "You're on npm >=3.3.0"]);
+      }
+    });
+  });
+}