globally replace let with var

.eslintrc.js

@@ -9,7 +9,6 @@ module.exports = {
   },
   rules: {
     'indent': ['error', 2],
-    'no-var': 'error',
     'prefer-const': 'error',
     'linebreak-style': ['error', 'unix'],
     'quotes': ['error', 'single'],

.gitignore

@@ -1,3 +1,4 @@
+.eslintcache
 .DS_Store
 node_modules
 dist

package.json

@@ -14,7 +14,8 @@
     "build:lib": "rollup --config rollup.config.prd.js",
     "build:min": "uglifyjs dist/subunit.js -ecma 5 -c -m -o dist/subunit.min.js",
     "build:copy-files": "babel-node ./scripts/copy-files.js",
-    "start": "rm -rf dist && mkdir dist && rollup -c rollup.config.dev.js --watch"
+    "start": "rm -rf dist && mkdir dist && rollup -c rollup.config.dev.js --watch",
+    "lint": "eslint src --quiet --cache && echo \"eslint: no lint errors\""
   },
   "repository": {
     "type": "git",

src/Transition.js

@@ -12,7 +12,7 @@ import size from 'd3-selection/src/selection/size';
 import empty from 'd3-selection/src/selection/empty';
 import each from 'd3-selection/src/selection/each';
 
-let id = 0;
+var id = 0;
 
 export function Transition(groups, parents, name, id) {
   this._groups = groups;

src/selection/append.js

@@ -11,7 +11,7 @@ export default function append(name) {
 }
 
 function selectionCreator(name) {
-  let Func;
+  var Func;
 
   if (typeof name === 'function') {
     Func = name; // SEND ANY CONSTRUCTOR

src/selection/attr.js

@@ -19,7 +19,7 @@ function selectionAttr(name, value) {
     if (name === 'tags' || name === 'class') {
       const arr = value.split(' ');
 
-      for (let i = 0; i < arr.length; i++) {
+      for (var i = 0; i < arr.length; i++) {
         this.__tags__.push(arr[i]);
       }
     } else if (name === 'position' || name === 'scale') {

src/selection/data.js

@@ -8,8 +8,8 @@ function bindIndex(parent, group, enter, update, exit, data) {
   const groupLength = group.length;
   const dataLength = data.length;
 
-  let i = 0;
-  let node;
+  var i = 0;
+  var node;
 
   for (; i < dataLength; ++i) {
     if ((node = group[i])) {
@@ -33,9 +33,9 @@ function bindKey(parent, group, enter, update, exit, data, key) {
   const dataLength = data.length;
   const keyValues = new Array(groupLength);
 
-  let i;
-  let node;
-  let keyValue;
+  var i;
+  var node;
+  var keyValue;
 
   for (i = 0; i < groupLength; ++i) {
     if ((node = group[i])) {
@@ -70,7 +70,7 @@ export default function(value, key) {
   if (!value) {
     const data = new Array(this.size());
 
-    let j = -1;
+    var j = -1;
 
     this.each(function(d) { data[++j] = d; });
 
@@ -88,7 +88,7 @@ export default function(value, key) {
   const update = new Array(m);
   const exit = new Array(m);
 
-  for (let j = 0; j < m; ++j) {
+  for (j = 0; j < m; ++j) {
     const parent = parents[j];
     const group = groups[j];
     const groupLength = group.length;
@@ -102,7 +102,7 @@ export default function(value, key) {
 
     bind(parent, group, enterGroup, updateGroup, exitGroup, data, key);
 
-    for (let i0 = 0, i1 = 0, previous, next; i0 < dataLength; ++i0) {
+    for (var i0 = 0, i1 = 0, previous, next; i0 < dataLength; ++i0) {
       if ((previous = enterGroup[i0])) {
         if (i0 >= i1) i1 = i0 + 1;
         while (!(next = updateGroup[i1]) && ++i1 < dataLength);

src/selection/each.js

@@ -6,8 +6,8 @@ export default function each(callback) {
 }
 
 export function selectionEach(groups, callback) {
-  for (let j = 0, m = groups.length; j < m; j++) {
-    for (let group = groups[j], i = 0, n = group.length, node; i < n; i++) {
+  for (var j = 0, m = groups.length; j < m; j++) {
+    for (var group = groups[j], i = 0, n = group.length, node; i < n; i++) {
       if ((node = group[i])) {
         callback(node, i, j);
       }

src/selection/filter.js

@@ -4,19 +4,19 @@ import { search } from '../utils/utils';
 export default function filter(fun) {
   const subgroups = [];
 
-  let subgroup;
-  let group;
-  let node;
+  var subgroup;
+  var group;
+  var node;
 
   if (typeof fun !== 'function') {
     fun = selectionFilter(fun);
   }
 
-  for (let j = 0, m = this.length; j < m; j++) {
+  for (var j = 0, m = this.length; j < m; j++) {
     subgroups.push(subgroup = []);
     subgroup.parentNode = (group = this[j]).parentNode;
 
-    for (let i = 0, n = group.length; i < n; i++) {
+    for (var i = 0, n = group.length; i < n; i++) {
       if ((node = group[i]) && fun.call(node, node.__data__, i, j)) {
         subgroup.push(node);
       }

src/selection/merge.js

@@ -9,7 +9,7 @@ export default function(selection) {
   const m = Math.min(m0, m1);
   const merges = new Array(m0);
 
-  let j = 0;
+  var j = 0;
 
   for (; j < m; ++j) {
 
@@ -18,7 +18,7 @@ export default function(selection) {
     const n = group0.length;
     const merge = merges[j] = new Array(n);
 
-    for (let node, i = 0; i < n; ++i) {
+    for (var node, i = 0; i < n; ++i) {
       if ((node = group0[i] || group1[i])) {
         merge[i] = node;
       }

src/selection/select.js

@@ -8,8 +8,8 @@ export default function select(selector) {
   const m = groups.length;
   const subgroups = new Array(m);
 
-  for (let j = 0; j < m; ++j) {
-    for (let group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
+  for (var j = 0; j < m; ++j) {
+    for (var group = groups[j], n = group.length, subgroup = subgroups[j] = new Array(n), node, subnode, i = 0; i < n; ++i) {
       if ((node = group[i]) && (subnode = selector.call(node, node.__data__, i, group))) {
         if ('__data__' in node) subnode.__data__ = node.__data__;
         subgroup[i] = subnode;

src/selection/selectAll.js

@@ -7,8 +7,8 @@ export default function selectAll(select) {
 
   if (typeof select !== 'function') select = selectionSelectorAll(select);
 
-  for (let groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
-    for (let group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
+  for (var groups = this._groups, m = groups.length, j = 0; j < m; ++j) {
+    for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
       if ((node = group[i])) {
         subgroups.push(select.call(node, node.__data__, i, group));
         parents.push(node);

src/selection/sort.js

@@ -11,12 +11,12 @@ export default function(compare) {
   const m = groups.length;
   const sortgroups = new Array(m);
 
-  for (let j = 0; j < m; ++j) {
+  for (var j = 0; j < m; ++j) {
     const group = groups[j];
     const n = group.length;
     const sortgroup = sortgroups[j] = new Array(n);
 
-    for (let node, i = 0; i < n; ++i) {
+    for (var node, i = 0; i < n; ++i) {
       if ((node = group[i])) {
         sortgroup[i] = node;
       }

src/selection/tagged.js

@@ -6,7 +6,7 @@ export default function tagged(name, value) {
       const node = this.node();
       const n = (name = selectionTags(name)).length;
 
-      let i = -1;
+      var i = -1;
 
       if ((value = node.__tags__.length)) {
         while (++i < n) {
@@ -41,7 +41,7 @@ function selectionTagged(name, value) {
   const n = name.length;
 
   function taggedConstant() {
-    let i = -1;
+    var i = -1;
 
     while (++i < n) {
       name[i](this, value);
@@ -51,7 +51,7 @@ function selectionTagged(name, value) {
   function taggedFunction() {
     const x = value.apply(this, arguments);
 
-    let i = -1;
+    var i = -1;
 
     while (++i < n) {
       name[i](this, x);

src/selection/transition.js

@@ -12,7 +12,7 @@ const defaultTiming = {
 };
 
 function inherit(node, id) {
-  let timing;
+  var timing;
 
   while (!(timing = node.__transition) || !(timing = timing[id])) {
     if (!(node = node.parentNode)) {
@@ -24,8 +24,8 @@ function inherit(node, id) {
 }
 
 export default function(name) {
-  let id;
-  let timing;
+  var id;
+  var timing;
 
   if (name instanceof Transition) {
     id = name._id, name = name._name;
@@ -36,8 +36,8 @@ export default function(name) {
   const groups = this._groups;
   const m = groups.length;
 
-  for (let j = 0; j < m; ++j) {
-    for (let group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
+  for (var j = 0; j < m; ++j) {
+    for (var group = groups[j], n = group.length, node, i = 0; i < n; ++i) {
       if ((node = group[i])) {
         schedule(node, name, id, i, group, timing || inherit(node, id));
       }

src/transition/tween.js

@@ -1,8 +1,8 @@
 import { get, set } from 'd3-transition/src/transition/schedule';
 
 function tweenFunction(id, name, value) {
-  let tween0;
-  let tween1;
+  var tween0;
+  var tween1;
 
   if (typeof value !== 'function') throw new Error;
 
@@ -11,9 +11,9 @@ function tweenFunction(id, name, value) {
     const tween = schedule.tween;
 
     if (tween !== tween0) {
-      let i;
-      let t;
-      let n;
+      var i;
+      var t;
+      var n;
 
       tween1 = (tween0 = tween).slice();
 
@@ -38,7 +38,7 @@ export default function(name, value) {
   if (arguments.length < 2) {
     const tween = get(this.node(), id).tween;
 
-    for (let i = 0, n = tween.length, t; i < n; ++i) {
+    for (var i = 0, n = tween.length, t; i < n; ++i) {
       if ((t = tween[i]).name === name) {
         return t.value;
       }

src/utils/utils.js

@@ -16,16 +16,16 @@ export function search(node, selector) {
         return;
       }
 
-      for (let i = 0; i < tagsArray.length; i++) {
+      for (var i = 0; i < tagsArray.length; i++) {
         if (node.__tags__.indexOf(tagsArray[i]) < 0) {
           return;
         }
       }
     } else {
       const keys = Object.keys(selector);
 
-      for (let i = 0; i < keys.length; i++) {
-        if (node[keys[i]] !== selector[keys[i]]) {
+      for (var j = 0; j < keys.length; j++) {
+        if (node[keys[j]] !== selector[keys[j]]) {
           return;
         }
       }
@@ -52,19 +52,19 @@ function toObject(val) {
 }
 
 export function assign(target, source) {
-  let pendingException;
+  var pendingException;
 
   const to = toObject(target);
 
   if (!source) {
     throw new Error('No source(s) provided to assign.');
   }
 
-  for (let s = 1; s < arguments.length; s++) {
+  for (var s = 1; s < arguments.length; s++) {
     const fromObj = arguments[s];
     const objKeys = Object.keys(Object(fromObj));
 
-    for (let i = 0; i < objKeys.length; i++) {
+    for (var i = 0; i < objKeys.length; i++) {
       try {
         to[objKeys[i]] = fromObj[objKeys[i]];
       } catch (err) {