Update eslint-config-babel to the latest version 🚀

package.json

@@ -25,7 +25,7 @@
     "codecov": "^1.0.1",
     "cross-env": "^2.0.0",
     "eslint": "^3.7.1",
-    "eslint-config-babel": "^3.0.0",
+    "eslint-config-babel": "^4.0.1",
     "eslint-plugin-babel": "^4.0.0",
     "eslint-plugin-flowtype": "^2.20.0",
     "flow-bin": "^0.37.0",

src/options.js

@@ -31,8 +31,8 @@ export const defaultOptions: {
 // Interpret and default an options object
 
 export function getOptions(opts?: Object): Object {
-  let options = {};
-  for (let key in defaultOptions) {
+  const options = {};
+  for (const key in defaultOptions) {
     options[key] = opts && key in opts ? opts[key] : defaultOptions[key];
   }
   return options;

src/parser/comments.js

@@ -41,7 +41,7 @@ pp.addComment = function (comment) {
 pp.processComment = function (node) {
   if (node.type === "Program" && node.body.length > 0) return;
 
-  let stack = this.state.commentStack;
+  const stack = this.state.commentStack;
 
   let lastChild, trailingComments, i, j;
 
@@ -63,7 +63,7 @@ pp.processComment = function (node) {
       this.state.trailingComments.length = 0;
     }
   } else {
-    let lastInStack = last(stack);
+    const lastInStack = last(stack);
     if (stack.length > 0 && lastInStack.trailingComments && lastInStack.trailingComments[0].start >= node.end) {
       trailingComments = lastInStack.trailingComments;
       lastInStack.trailingComments = null;

src/parser/index.js

@@ -60,7 +60,7 @@ export default class Parser extends Tokenizer {
     pluginNames.push("flow");
 
     pluginNames.forEach((name) => {
-      let plugin = plugins[name];
+      const plugin = plugins[name];
       if (plugin) plugin(this);
     });
   }
@@ -73,19 +73,19 @@ export default class Parser extends Tokenizer {
       return { "*": true };
     }
 
-    let pluginMap = {};
+    const pluginMap = {};
 
     if (pluginList.indexOf("flow") >= 0) {
       // ensure flow plugin loads last
       pluginList = pluginList.filter((plugin) => plugin !== "flow");
       pluginList.push("flow");
     }
 
-    for (let name of pluginList) {
+    for (const name of pluginList) {
       if (!pluginMap[name]) {
         pluginMap[name] = true;
 
-        let plugin = plugins[name];
+        const plugin = plugins[name];
         if (plugin) plugin(this);
       }
     }
@@ -100,8 +100,8 @@ export default class Parser extends Tokenizer {
       body: Array<Object>
     }
   } {
-    let file = this.startNode();
-    let program = this.startNode();
+    const file = this.startNode();
+    const program = this.startNode();
     this.nextToken();
     return this.parseTopLevel(file, program);
   }

src/parser/location.js

@@ -10,9 +10,9 @@ const pp = Parser.prototype;
 // message.
 
 pp.raise = function (pos, message) {
-  let loc = getLineInfo(this.input, pos);
+  const loc = getLineInfo(this.input, pos);
   message += ` (${loc.line}:${loc.column})`;
-  let err = new SyntaxError(message);
+  const err = new SyntaxError(message);
   err.pos = pos;
   err.loc = loc;
   throw err;

src/parser/lval.js

@@ -19,7 +19,7 @@ pp.toAssignable = function (node, isBinding, contextDescription) {
 
       case "ObjectExpression":
         node.type = "ObjectPattern";
-        for (let prop of (node.properties: Array<Object>)) {
+        for (const prop of (node.properties: Array<Object>)) {
           if (prop.type === "ObjectMethod") {
             if (prop.kind === "get" || prop.kind === "set") {
               this.raise(prop.key.start, "Object pattern can't contain getter or setter");
@@ -72,12 +72,12 @@ pp.toAssignable = function (node, isBinding, contextDescription) {
 pp.toAssignableList = function (exprList, isBinding, contextDescription) {
   let end = exprList.length;
   if (end) {
-    let last = exprList[end - 1];
+    const last = exprList[end - 1];
     if (last && last.type === "RestElement") {
       --end;
     } else if (last && last.type === "SpreadElement") {
       last.type = "RestElement";
-      let arg = last.argument;
+      const arg = last.argument;
       this.toAssignable(arg, isBinding, contextDescription);
       if (arg.type !== "Identifier" && arg.type !== "MemberExpression" && arg.type !== "ArrayPattern") {
         this.unexpected(arg.start);
@@ -86,7 +86,7 @@ pp.toAssignableList = function (exprList, isBinding, contextDescription) {
     }
   }
   for (let i = 0; i < end; i++) {
-    let elt = exprList[i];
+    const elt = exprList[i];
     if (elt) this.toAssignable(elt, isBinding, contextDescription);
   }
   return exprList;
@@ -101,14 +101,14 @@ pp.toReferencedList = function (exprList) {
 // Parses spread element.
 
 pp.parseSpread = function (refShorthandDefaultPos) {
-  let node = this.startNode();
+  const node = this.startNode();
   this.next();
   node.argument = this.parseMaybeAssign(false, refShorthandDefaultPos);
   return this.finishNode(node, "SpreadElement");
 };
 
 pp.parseRest = function () {
-  let node = this.startNode();
+  const node = this.startNode();
   this.next();
   node.argument = this.parseBindingIdentifier();
   return this.finishNode(node, "RestElement");
@@ -133,7 +133,7 @@ pp.parseBindingAtom = function () {
       return this.parseIdentifier(true);
 
     case tt.bracketL:
-      let node = this.startNode();
+      const node = this.startNode();
       this.next();
       node.elements = this.parseBindingList(tt.bracketR, true);
       return this.finishNode(node, "ArrayPattern");
@@ -147,7 +147,7 @@ pp.parseBindingAtom = function () {
 };
 
 pp.parseBindingList = function (close, allowEmpty) {
-  let elts = [];
+  const elts = [];
   let first = true;
   while (!this.eat(close)) {
     if (first) {
@@ -164,11 +164,11 @@ pp.parseBindingList = function (close, allowEmpty) {
       this.expect(close);
       break;
     } else {
-      let decorators = [];
+      const decorators = [];
       while (this.match(tt.at)) {
         decorators.push(this.parseDecorator());
       }
-      let left = this.parseMaybeDefault();
+      const left = this.parseMaybeDefault();
       if (decorators.length) {
         left.decorators = decorators;
       }
@@ -191,7 +191,7 @@ pp.parseMaybeDefault = function (startPos, startLoc, left) {
   left = left || this.parseBindingAtom();
   if (!this.eat(tt.eq)) return left;
 
-  let node = this.startNodeAt(startPos, startLoc);
+  const node = this.startNodeAt(startPos, startLoc);
   node.left = left;
   node.right = this.parseMaybeAssign();
   return this.finishNode(node, "AssignmentPattern");
@@ -217,7 +217,7 @@ pp.checkLVal = function (expr, isBinding, checkClashes, contextDescription) {
         //   true
         //   > obj.__proto__
         //   null
-        let key = `_${expr.name}`;
+        const key = `_${expr.name}`;
 
         if (checkClashes[key]) {
           this.raise(expr.start, "Argument name clash in strict mode");
@@ -239,7 +239,7 @@ pp.checkLVal = function (expr, isBinding, checkClashes, contextDescription) {
       break;
 
     case "ArrayPattern":
-      for (let elem of (expr.elements: Array<Object>)) {
+      for (const elem of (expr.elements: Array<Object>)) {
         if (elem) this.checkLVal(elem, isBinding, checkClashes, "array destructuring pattern");
       }
       break;

src/parser/node.js

@@ -22,7 +22,7 @@ class Node {
 
   __clone(): Node {
     const node2 = new Node;
-    for (let key in this) {
+    for (const key in this) {
       // Do not clone comments that are already attached to the node
       if (commentKeys.indexOf(key) < 0) {
         node2[key] = this[key];