From 76e12a3caefdee80144564d02a03f3ce9774a509 Mon Sep 17 00:00:00 2001
From: Brian Ng <bng412@gmail.com>
Date: Mon, 2 Jan 2017 22:55:32 -0600
Subject: [PATCH] Show error if target version is not a number (#107)

---
 experimental/babel-preset-env/src/index.js  |  7 ++++---
 experimental/babel-preset-env/test/index.js | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/experimental/babel-preset-env/src/index.js b/experimental/babel-preset-env/src/index.js
index 911909dea7..791848c2a7 100644
--- a/experimental/babel-preset-env/src/index.js
+++ b/experimental/babel-preset-env/src/index.js
@@ -50,11 +50,12 @@ export const isPluginRequired = (supportedEnvironments, plugin) => {
       const lowestImplementedVersion = plugin[environment];
       const lowestTargetedVersion = supportedEnvironments[environment];
 
-      if (lowestTargetedVersion < lowestImplementedVersion) {
-        return true;
+      if (typeof lowestTargetedVersion === "string") {
+        throw new Error(`Target version must be a number, 
+          '${lowestTargetedVersion}' was given for '${environment}'`);
       }
 
-      return false;
+      return lowestTargetedVersion < lowestImplementedVersion;
     });
 
   return isRequiredForEnvironments.length > 0 ? true : false;
diff --git a/experimental/babel-preset-env/test/index.js b/experimental/babel-preset-env/test/index.js
index e72908f428..b43db5c5c7 100644
--- a/experimental/babel-preset-env/test/index.js
+++ b/experimental/babel-preset-env/test/index.js
@@ -158,6 +158,20 @@ describe("babel-preset-env", () => {
         babelPresetEnv.isPluginRequired(targets, plugin);
       }, Error);
     });
+
+    it("will throw if target version is not a number", () => {
+      const plugin = {
+        "node": 6,
+      };
+
+      const targets = {
+        "node": "6.5",
+      };
+
+      assert.throws(() => {
+        babelPresetEnv.isPluginRequired(targets, plugin);
+      }, Error);
+    });
   });
 
   describe("validateLooseOption", () => {