custom babel target for each node version

Author: leonardodino

lib/build.js

@@ -4,14 +4,22 @@ var conf = require("./config");
 var webpack = require("webpack");
 var merge = require("webpack-merge");
 
+// custom babel target for each node version
+function getBabelTarget(){
+  var runtimes = ["nodejs8.10", "nodejs4.3.2", "nodejs6.10.3"];
+  var current = process.env["AWS_LAMBDA_JS_RUNTIME"] || "nodejs6.10.3";
+  var unknown = runtimes.indexOf(current) === -1;
+  return unknown ? "6.10" : current.replace(/^nodejs/);
+}
+
 function webpackConfig(dir, additionalConfig) {
   var config = conf.load();
   var babelOpts = {cacheDirectory: true};
   if (!fs.existsSync(path.join(process.cwd(), '.babelrc'))) {
     babelOpts.presets = [
       ["env", {
         targets: {
-          node: "6.10"
+          node: getBabelTarget()
         }
       }]
     ];