Refactor code-style

Author: wooorm

index.js

@@ -16,7 +16,7 @@ import {convert} from 'unist-util-is'
  * @property {boolean} [cascade=true] Whether to drop parent nodes if they had children, but all their children were filtered out.
  */
 
-var own = {}.hasOwnProperty
+const own = {}.hasOwnProperty
 
 export const filter =
   /**
@@ -38,8 +38,8 @@ export const filter =
      * @returns {Node|null}
      */
     function (tree, options, test) {
-      var is = convert(test || options)
-      var cascade =
+      const is = convert(test || options)
+      const cascade =
         options.cascade === undefined || options.cascade === null
           ? true
           : options.cascade
@@ -54,15 +54,13 @@ export const filter =
        */
       function preorder(node, index, parent) {
         /** @type {Array.<Node>} */
-        var children = []
+        const children = []
         /** @type {number} */
-        var childIndex
+        let childIndex
         /** @type {Node} */
-        var result
-        /** @type {typeof node} */
-        var next
+        let result
         /** @type {string} */
-        var key
+        let key
 
         if (!is(node, index, parent)) return null
 
@@ -81,12 +79,14 @@ export const filter =
           }
 
           // @ts-ignore Looks like a parent.
-          if (cascade && node.children.length && !children.length) return null
+          if (cascade && node.children.length > 0 && children.length === 0)
+            return null
         }
 
         // Create a shallow clone, using the new children.
+        /** @type {typeof node} */
         // @ts-ignore all the fields will be copied over.
-        next = {}
+        const next = {}
 
         for (key in node) {
           /* istanbul ignore else - Prototype injection. */

package.json

@@ -68,12 +68,7 @@
     "trailingComma": "none"
   },
   "xo": {
-    "prettier": true,
-    "rules": {
-      "no-var": "off",
-      "prefer-arrow-callback": "off",
-      "unicorn/explicit-length-check": "off"
-    }
+    "prettier": true
   },
   "remarkConfig": {
     "plugins": [

readme.md

@@ -28,13 +28,13 @@ npm install unist-util-filter
 import {u} from 'unist-builder'
 import {filter} from 'unist-util-filter'
 
-var tree = u('root', [
+const tree = u('root', [
   u('leaf', '1'),
   u('node', [u('leaf', '2'), u('node', [u('leaf', '3')])]),
   u('leaf', '4')
 ])
 
-var newTree = filter(tree, node => node.type !== 'leaf' || node.value % 2 === 0)
+const newTree = filter(tree, node => node.type !== 'leaf' || node.value % 2 === 0)
 
 console.dir(newTree, {depth: null})
 ```

test.js

@@ -7,9 +7,9 @@ import test from 'tape'
 import {u} from 'unist-builder'
 import {filter} from './index.js'
 
-test('should not traverse into children of filtered out nodes', function (t) {
-  var tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
-  var types = {}
+test('should not traverse into children of filtered out nodes', (t) => {
+  const tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+  const types = {}
 
   t.deepEqual(filter(tree, predicate), u('root', [u('leaf', '2')]))
   t.deepEqual(types, {root: 1, node: 1, leaf: 1})
@@ -25,8 +25,8 @@ test('should not traverse into children of filtered out nodes', function (t) {
   }
 })
 
-test('should return `null` if root node is filtered out', function (t) {
-  var tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+test('should return `null` if root node is filtered out', (t) => {
+  const tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
 
   t.deepEqual(filter(tree, predicate), null)
 
@@ -37,8 +37,8 @@ test('should return `null` if root node is filtered out', function (t) {
   }
 })
 
-test('should cascade-remove parent nodes', function (t) {
-  var tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+test('should cascade-remove parent nodes', (t) => {
+  const tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
 
   t.deepEqual(filter(tree, notOne), u('root', [u('leaf', '2')]))
   t.deepEqual(filter(tree, notLeaf), null)
@@ -61,18 +61,18 @@ test('should cascade-remove parent nodes', function (t) {
   }
 })
 
-test('should not cascade-remove nodes that were empty initially', function (t) {
-  var tree = u('node', [u('node', []), u('node', [u('leaf')])])
+test('should not cascade-remove nodes that were empty initially', (t) => {
+  const tree = u('node', [u('node', []), u('node', [u('leaf')])])
 
   t.deepEqual(filter(tree, 'node'), u('node', [u('node', [])]))
 
   t.end()
 })
 
-test('should call iterator with `index` and `parent` args', function (t) {
-  var tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+test('should call iterator with `index` and `parent` args', (t) => {
+  const tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
   /** @type {Array.<[Node, number|undefined, Parent|undefined]>} */
-  var callLog = []
+  const callLog = []
 
   t.deepEqual(filter(tree, predicate), tree)
 
@@ -92,8 +92,8 @@ test('should call iterator with `index` and `parent` args', function (t) {
   }
 })
 
-test('should support type and node tests', function (t) {
-  var tree = u('node', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+test('should support type and node tests', (t) => {
+  const tree = u('node', [u('node', [u('leaf', '1')]), u('leaf', '2')])
 
   t.deepEqual(filter(tree, 'node'), null)
   t.deepEqual(
@@ -105,8 +105,8 @@ test('should support type and node tests', function (t) {
   t.end()
 })
 
-test('opts.cascade', function (t) {
-  var tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
+test('opts.cascade', (t) => {
+  const tree = u('root', [u('node', [u('leaf', '1')]), u('leaf', '2')])
 
   t.deepEqual(
     filter(tree, {cascade: true}, predicate),
@@ -130,8 +130,8 @@ test('opts.cascade', function (t) {
   }
 })
 
-test('example from README', function (t) {
-  var tree = u('root', [
+test('example from README', (t) => {
+  const tree = u('root', [
     u('leaf', '1'),
     u('node', [u('leaf', '2'), u('node', [u('leaf', '3')])]),
     u('leaf', '4')