Refactor code-style

Author: wooorm

index.js

@@ -11,15 +11,17 @@
  * @property {boolean} trailing
  */
 
+const own = {}.hasOwnProperty
+
 /**
  * Attach semistandard estree comment nodes to the tree.
  *
  * @param {EstreeNode} tree
  * @param {EstreeComment[]} [comments]
  */
 export function attachComments(tree, comments) {
-  var list = (comments || []).concat().sort(compare)
-  if (list.length) walk(tree, {comments: list, index: 0})
+  const list = (comments || []).concat().sort(compare)
+  if (list.length > 0) walk(tree, {comments: list, index: 0})
   return tree
 }
 
@@ -30,38 +32,37 @@ export function attachComments(tree, comments) {
  * @param {State} state
  */
 function walk(node, state) {
-  /** @type {EstreeNode[]} */
-  var children = []
-  /** @type {EstreeComment[]} */
-  var comments = []
-  /** @type {string} */
-  var key
-  /** @type {EstreeNode|EstreeNode[]} */
-  var value
-  /** @type {number} */
-  var index
-
   // Done, we can quit.
   if (state.index === state.comments.length) {
     return
   }
 
+  /** @type {EstreeNode[]} */
+  const children = []
+  /** @type {EstreeComment[]} */
+  const comments = []
+  /** @type {string} */
+  let key
+
   // Find all children of `node`
   for (key in node) {
-    value = node[key]
-
-    // Ignore comments.
-    if (value && typeof value === 'object' && key !== 'comments') {
-      if (Array.isArray(value)) {
-        index = -1
-
-        while (++index < value.length) {
-          if (value[index] && typeof value[index].type === 'string') {
-            children.push(value[index])
+    if (own.call(node, key)) {
+      /** @type {EstreeNode|EstreeNode[]} */
+      const value = node[key]
+
+      // Ignore comments.
+      if (value && typeof value === 'object' && key !== 'comments') {
+        if (Array.isArray(value)) {
+          let index = -1
+
+          while (++index < value.length) {
+            if (value[index] && typeof value[index].type === 'string') {
+              children.push(value[index])
+            }
           }
+        } else if (typeof value.type === 'string') {
+          children.push(value)
         }
-      } else if (typeof value.type === 'string') {
-        children.push(value)
       }
     }
   }
@@ -72,7 +73,7 @@ function walk(node, state) {
   // Initial comments.
   comments.push(...slice(state, node, false, {leading: true, trailing: false}))
 
-  index = -1
+  let index = -1
 
   while (++index < children.length) {
     walk(children[index], state)
@@ -82,11 +83,11 @@ function walk(node, state) {
   comments.push(
     ...slice(state, node, true, {
       leading: false,
-      trailing: Boolean(children.length)
+      trailing: children.length > 0
     })
   )
 
-  if (comments.length) {
+  if (comments.length > 0) {
     // @ts-expect-error, yes, because they’re nonstandard.
     node.comments = comments
   }
@@ -100,7 +101,7 @@ function walk(node, state) {
  */
 function slice(state, node, compareEnd, fields) {
   /** @type {EstreeComment[]} */
-  var result = []
+  const result = []
 
   while (
     state.comments[state.index] &&
@@ -119,7 +120,7 @@ function slice(state, node, compareEnd, fields) {
  * @returns {number}
  */
 function compare(left, right, compareEnd) {
-  var field = compareEnd ? 'end' : 'start'
+  const field = compareEnd ? 'end' : 'start'
 
   // Offsets.
   if (left.range && right.range) {
@@ -141,5 +142,5 @@ function compare(left, right, compareEnd) {
     return left.start - right[field]
   }
 
-  return NaN
+  return Number.NaN
 }

package.json

@@ -70,12 +70,7 @@
   "xo": {
     "prettier": true,
     "rules": {
-      "no-var": "off",
-      "prefer-arrow-callback": "off",
-      "guard-for-in": "off",
-      "max-depth": "off",
-      "unicorn/explicit-length-check": "off",
-      "unicorn/prefer-number-properties": "off"
+      "max-depth": "off"
     }
   },
   "remarkConfig": {

readme.md

@@ -45,8 +45,8 @@ import * as acorn from 'acorn'
 import recast from 'recast'
 import {attachComments} from 'estree-util-attach-comments'
 
-var comments = []
-var tree = acorn.parse(code, {ecmaVersion: 2020, onComment: comments})
+const comments = []
+const tree = acorn.parse(code, {ecmaVersion: 2020, onComment: comments})
 
 attachComments(tree, comments)
 

test.js

@@ -10,7 +10,7 @@ import {attachComments} from './index.js'
  * @typedef {import('estree').Comment} EstreeComment
  */
 
-test('estree-attach-comments (recast)', function (t) {
+test('estree-attach-comments (recast)', (t) => {
   t.equal(
     recast.print(attachComments(...parse(''))).code,
     '',
@@ -79,10 +79,10 @@ test('estree-attach-comments (recast)', function (t) {
   )
 
   /** @type {EstreeComment[]} */
-  var comments = []
+  let comments = []
   /** @type {EstreeProgram} */
   // @ts-expect-error
-  var tree = acornParse('/* 1 */ a /* 2 */ + /* 3 */ 1', {
+  let tree = acornParse('/* 1 */ a /* 2 */ + /* 3 */ 1', {
     ecmaVersion: 2020,
     // @ts-expect-error
     onComment: comments
@@ -170,10 +170,10 @@ test('estree-attach-comments (recast)', function (t) {
  */
 function parse(doc) {
   /** @type {EstreeComment[]} */
-  var comments = []
+  const comments = []
   /** @type {EstreeProgram} */
   // @ts-expect-error
-  var tree = acornParse(doc, {ecmaVersion: 2020, onComment: comments})
+  const tree = acornParse(doc, {ecmaVersion: 2020, onComment: comments})
   return [tree, comments]
 }
 
@@ -188,7 +188,7 @@ function removePositions(value) {
     /**
      * @param {EstreeNode} node
      */
-    function (node) {
+    (node) => {
       // @ts-expect-error they most certainly exist.
       delete node.start
       // @ts-expect-error they most certainly exist.