Modernize the loader file to ES6

Author: bergie

Diff for: .eslintrc.json

@@ -1,3 +1,6 @@
 {
-  "extends": "airbnb-base"
+  "extends": "airbnb-base",
+  "env": {
+    "browser": true
+  }
 }

Diff for: lib/loader.js

@@ -1,106 +1,126 @@
-/* eslint-disable */
-exports.registerCustomLoaders = function (loader, loaders, callback) {
+function registerCustomLoaders(loader, loaders, callback) {
   if (!loaders.length) {
-    return callback();
+    callback();
+    return;
   }
-  var customLoader = loaders.shift();
-  loader.registerLoader(customLoader, function (err) {
+  const customLoader = loaders.shift();
+  loader.registerLoader(customLoader, (err) => {
     if (err) {
-      return callback(err);
+      callback(err);
+      return;
     }
     exports.registerCustomLoaders(loader, loaders, callback);
   });
-};
-
+}
 
-exports.setSource = function (sources, loader, packageId, name, source, language, callback) {
-  var implementation;
-  var originalSource = source;
+function setSource(sources, loader, packageId, name, originalSource, language, callback) {
+  let implementation;
+  let source = originalSource;
   // Transpiling
   if (language === 'coffeescript') {
     if (typeof window !== 'undefined' && !window.CoffeeScript) {
-      return callback(new Error('CoffeeScript compiler needed for ' + packageId + '/' + name + ' not available'));
+      callback(new Error(`CoffeeScript compiler needed for ${packageId}/${name} not available`));
+      return;
     }
     try {
       source = window.CoffeeScript.compile(source, {
-        bare: true
+        bare: true,
       });
     } catch (e) {
-      return callback(e);
+      callback(e);
+      return;
     }
   }
   if (language === 'es6' || language === 'es2015') {
     if (typeof window !== 'undefined' && window.babel) {
       try {
         source = window.babel.transform(source).code;
       } catch (e) {
-        return callback(e);
+        callback(e);
+        return;
       }
     }
   }
   // Eval the contents to get a runnable component
   try {
-    var withExports = '(function () { var exports = {}; ' + source + '; return exports; })();';
+    const withExports = `(function () { var exports = {}; ${source}; return exports; })();`;
+    // eslint-disable-next-line no-eval
     implementation = eval(withExports);
   } catch (e) {
-    return callback(e);
+    callback(e);
+    return;
   }
 
   if (typeof implementation !== 'function' && (!implementation.getComponent || typeof implementation.getComponent !== 'function')) {
-    return callback(new Error('Provided source for ' + packageId + '/' + name + ' failed to create a runnable component'));
+    callback(new Error(`Provided source for ${packageId}/${name} failed to create a runnable component`));
+    return;
   }
 
-  var fullName = packageId + '/' + name;
+  const fullName = `${packageId}/${name}`;
+  // eslint-disable-next-line no-param-reassign
   sources[fullName] = {
-    language: language,
-    source: originalSource
+    language,
+    source: originalSource,
   };
 
   loader.registerComponent(packageId, name, implementation, callback);
-};
+}
 
-exports.getSource = function (sources, loader, name, callback) {
+function getSource(sources, loader, name, callback) {
   if (!loader.components[name]) {
-    return callback(new Error('Component ' + name + ' not available'));
+    callback(new Error(`Component ${name} not available`));
+    return;
   }
-  var component = loader.components[name];
+  const component = loader.components[name];
+  let componentData;
   if (name.indexOf('/') !== -1) {
-    var nameParts = name.split('/');
-    var componentData = {
+    const nameParts = name.split('/');
+    componentData = {
       name: nameParts[1],
-      library: nameParts[0]
+      library: nameParts[0],
     };
   } else {
-    var componentData = {
-      name: name,
-      library: ''
+    componentData = {
+      name,
+      library: '',
     };
   }
   if (loader.isGraph(component)) {
     componentData.code = JSON.stringify(component, null, 2);
     componentData.language = 'json';
-    return callback(null, componentData);
-  } else if (sources[name]) {
+    callback(null, componentData);
+    return;
+  } if (sources[name]) {
     componentData.code = sources[name].source;
     componentData.language = sources[name].language;
     componentData.tests = sources[name].tests;
-    return callback(null, componentData);
-  } else if (typeof component === 'function') {
+    callback(null, componentData);
+    return;
+  } if (typeof component === 'function') {
     componentData.code = component.toString();
     componentData.language = 'javascript';
-    return callback(null, componentData);
-  } else if (typeof component.getComponent === 'function') {
+    callback(null, componentData);
+    return;
+  } if (typeof component.getComponent === 'function') {
     componentData.code = component.getComponent.toString();
     componentData.language = 'javascript';
-    return callback(null, componentData);
+    callback(null, componentData);
+    return;
   }
-  return callback(new Error('Unable to get sources for ' + name));
-};
+  callback(new Error(`Unable to get sources for ${name}`));
+}
 
-exports.getLanguages = function () {
-  var languages = ['javascript', 'es2015'];
+function getLanguages() {
+  const languages = ['javascript', 'es2015'];
   if (typeof window !== 'undefined' && window.CoffeeScript) {
     languages.push('coffeescript');
   }
   return languages;
+}
+
+module.exports = {
+  registerCustomLoaders,
+  setSource,
+  getSource,
+  getLanguages,
 };