Use ESM

.gitignore

@@ -1,6 +1,5 @@
 .DS_Store
 *.log
-.nyc_output/
 coverage/
 node_modules/
 yarn.lock

.prettierignore

@@ -1,3 +1,2 @@
 coverage/
-*.json
 *.md

index.js

@@ -1,22 +1,14 @@
-'use strict'
+import {any} from './lib/any.js'
+import {parse} from './lib/parse.js'
 
-exports.matches = matches
-exports.selectAll = selectAll
-exports.select = select
-
-var any = require('./lib/any')
-var parse = require('./lib/parse')
-
-function matches(selector, node) {
-  return Boolean(
-    any(parse(selector), node, {one: true, shallow: true, any: any})[0]
-  )
+export function matches(selector, node) {
+  return Boolean(any(parse(selector), node, {one: true, shallow: true, any})[0])
 }
 
-function select(selector, node) {
-  return any(parse(selector), node, {one: true, any: any})[0] || null
+export function select(selector, node) {
+  return any(parse(selector), node, {one: true, any})[0] || null
 }
 
-function selectAll(selector, node) {
-  return any(parse(selector), node, {any: any})
+export function selectAll(selector, node) {
+  return any(parse(selector), node, {any})
 }

lib/any.js

@@ -1,23 +1,15 @@
-'use strict'
-
-module.exports = match
-
-var zwitch = require('zwitch')
-var pseudo = require('./pseudo')
-var test = require('./test')
-var nest = require('./nest')
+import {zwitch} from 'zwitch'
+import {pseudo} from './pseudo.js'
+import {test} from './test.js'
+import {nest} from './nest.js'
 
 var type = zwitch('type', {
   unknown: unknownType,
   invalid: invalidType,
-  handlers: {
-    selectors: selectors,
-    ruleSet: ruleSet,
-    rule: rule
-  }
+  handlers: {selectors, ruleSet, rule}
 })
 
-function match(query, node, state) {
+export function any(query, node, state) {
   return query && node ? type(query, node, state) : []
 }
 
@@ -50,7 +42,7 @@ function rule(query, tree, state) {
     null,
     configure(query, {
       scopeNodes: tree.type === 'root' ? tree.children : [tree],
-      iterator: iterator,
+      iterator,
       one: state.one,
       shallow: state.shallow,
       any: state.any
@@ -76,7 +68,7 @@ function configure(query, state) {
   var index = -1
 
   while (++index < pseudos.length) {
-    if (pseudo.needsIndex.indexOf(pseudos[index].name) > -1) {
+    if (pseudo.needsIndex.includes(pseudos[index].name)) {
       state.index = true
       break
     }
@@ -85,12 +77,14 @@ function configure(query, state) {
   return state
 }
 
-/* istanbul ignore next - Shouldn’t be invoked, all data is handled. */
+// Shouldn’t be invoked, all data is handled.
+/* c8 ignore next 3 */
 function unknownType(query) {
   throw new Error('Unknown type `' + query.type + '`')
 }
 
-/* istanbul ignore next - Shouldn’t be invoked, parser gives correct data. */
+// Shouldn’t be invoked, parser gives correct data.
+/* c8 ignore next 3 */
 function invalidType() {
   throw new Error('Invalid type')
 }
@@ -118,12 +112,13 @@ function collector(one) {
 
   function collectOne(node) {
     if (one) {
-      /* istanbul ignore if - shouldn’t happen, safeguards performance problems. */
+      /* Shouldn’t happen, safeguards performance problems. */
+      /* c8 ignore next */
       if (found) throw new Error('Cannot collect multiple nodes')
 
       found = true
     }
 
-    if (result.indexOf(node) < 0) result.push(node)
+    if (!result.includes(node)) result.push(node)
   }
 }

lib/attribute.js

@@ -1,8 +1,4 @@
-'use strict'
-
-module.exports = match
-
-var zwitch = require('zwitch')
+import {zwitch} from 'zwitch'
 
 var handle = zwitch('operator', {
   unknown: unknownOperator,
@@ -16,7 +12,7 @@ var handle = zwitch('operator', {
   }
 })
 
-function match(query, node) {
+export function attribute(query, node) {
   var attrs = query.attrs
   var index = -1
 
@@ -29,25 +25,25 @@ function match(query, node) {
 
 // [attr]
 function exists(query, node) {
-  return node[query.name] != null
+  return node[query.name] !== null && node[query.name] !== undefined
 }
 
 // [attr=value]
 function exact(query, node) {
-  return node[query.name] != null && String(node[query.name]) === query.value
+  return exists(query, node) && String(node[query.name]) === query.value
 }
 
 // [attr~=value]
 function containsArray(query, node) {
   var value = node[query.name]
 
-  if (value == null) return false
+  if (value === null || value === undefined) return false
 
   // If this is an array, and the query is contained in it, return true.
   if (
     typeof value === 'object' &&
     'length' in value &&
-    value.indexOf(query.value) > -1
+    value.includes(query.value)
   ) {
     return true
   }
@@ -79,10 +75,11 @@ function ends(query, node) {
 // [attr*=value]
 function containsString(query, node) {
   var value = node[query.name]
-  return typeof value === 'string' && value.indexOf(query.value) > -1
+  return typeof value === 'string' && value.includes(query.value)
 }
 
-/* istanbul ignore next - Shouldn’t be invoked, Parser throws an error instead. */
+// Shouldn’t be invoked, Parser throws an error instead.
+/* c8 ignore next 3 */
 function unknownOperator(query) {
   throw new Error('Unknown operator `' + query.operator + '`')
 }

lib/name.js

@@ -1,7 +1,3 @@
-'use strict'
-
-module.exports = match
-
-function match(query, node) {
+export function name(query, node) {
   return query.tagName === '*' || query.tagName === node.type
 }

lib/nest.js

@@ -1,8 +1,4 @@
-'use strict'
-
-module.exports = match
-
-var zwitch = require('zwitch')
+import {zwitch} from 'zwitch'
 
 var own = {}.hasOwnProperty
 
@@ -17,36 +13,38 @@ var handle = zwitch('nestingOperator', {
   }
 })
 
-function match(query, node, index, parent, state) {
+export function nest(query, node, index, parent, state) {
   return handle(query, node, index, parent, state)
 }
 
-/* istanbul ignore next - Shouldn’t be invoked, parser gives correct data. */
+// Shouldn’t be invoked, parser gives correct data.
+/* c8 ignore next 3 */
 function unknownNesting(query) {
   throw new Error('Unexpected nesting `' + query.nestingOperator + '`')
 }
 
 function topScan(query, node, index, parent, state) {
-  /* istanbul ignore if - Shouldn’t happen. */
+  // Shouldn’t happen.
+  /* c8 ignore next 3 */
   if (parent) {
     throw new Error('topScan is supposed to be called from the root node')
   }
 
-  state.iterator.apply(null, arguments)
+  state.iterator(...arguments)
 
-  if (!state.shallow) descendant.apply(this, arguments)
+  if (!state.shallow) descendant.call(this, ...arguments)
 }
 
 function descendant(query, node, index, parent, state) {
   var previous = state.iterator
 
   state.iterator = iterator
 
-  child.apply(this, arguments)
+  child.call(this, ...arguments)
 
   function iterator(_, node, index, parent, state) {
     state.iterator = previous
-    previous.apply(this, arguments)
+    previous.call(this, ...arguments)
     state.iterator = iterator
 
     if (state.one && state.found) return
@@ -56,13 +54,14 @@ function descendant(query, node, index, parent, state) {
 }
 
 function child(query, node, index, parent, state) {
-  if (!node.children || !node.children.length) return
+  if (!node.children || node.children.length === 0) return
 
   walkIterator(query, node, state).each().done()
 }
 
 function adjacentSibling(query, node, index, parent, state) {
-  /* istanbul ignore if - Shouldn’t happen. */
+  // Shouldn’t happen.
+  /* c8 ignore next */
   if (!parent) return
 
   walkIterator(query, parent, state)
@@ -73,7 +72,8 @@ function adjacentSibling(query, node, index, parent, state) {
 }
 
 function generalSibling(query, node, index, parent, state) {
-  /* istanbul ignore if - Shouldn’t happen. */
+  // Shouldn’t happen.
+  /* c8 ignore next */
   if (!parent) return
 
   walkIterator(query, parent, state)
@@ -91,7 +91,7 @@ function walkIterator(query, parent, state) {
   return {
     prefillTypeIndex: rangeDefaults(prefillTypeIndex),
     each: rangeDefaults(each),
-    done: done
+    done
   }
 
   function done() {
@@ -149,8 +149,9 @@ function walkIterator(query, parent, state) {
     return rangeDefault
 
     function rangeDefault(start, end) {
-      if (start == null || start < 0) start = 0
-      if (end == null || end > siblings.length) end = siblings.length
+      if (start === null || start === undefined || start < 0) start = 0
+      if (end === null || end === undefined || end > siblings.length)
+        end = siblings.length
       return iterator.call(this, start, end)
     }
   }

lib/parse.js

@@ -1,28 +1,25 @@
-'use strict'
+import {CssSelectorParser} from 'css-selector-parser'
+import nthCheck from 'nth-check'
+import {zwitch} from 'zwitch'
 
-module.exports = parse
+var nth = new Set([
+  'nth-child',
+  'nth-last-child',
+  'nth-of-type',
+  'nth-last-of-type'
+])
 
-var Parser = require('css-selector-parser').CssSelectorParser
-var zwitch = require('zwitch')
-var nthCheck = require('nth-check').default
-
-var nth = ['nth-child', 'nth-last-child', 'nth-of-type', 'nth-last-of-type']
-
-var parser = new Parser()
+var parser = new CssSelectorParser()
 
 var compile = zwitch('type', {
-  handlers: {
-    selectors: selectors,
-    ruleSet: ruleSet,
-    rule: rule
-  }
+  handlers: {selectors, ruleSet, rule}
 })
 
 parser.registerAttrEqualityMods('~', '^', '$', '*')
 parser.registerSelectorPseudos('any', 'matches', 'not', 'has')
 parser.registerNestingOperators('>', '+', '~')
 
-function parse(selector) {
+export function parse(selector) {
   if (typeof selector !== 'string') {
     throw new TypeError('Expected `string` as selector, not `' + selector + '`')
   }
@@ -53,8 +50,8 @@ function rule(query) {
   while (++index < pseudos.length) {
     pseudo = pseudos[index]
 
-    if (nth.indexOf(pseudo.name) > -1) {
-      pseudo.value = nthCheck(pseudo.value)
+    if (nth.has(pseudo.name)) {
+      pseudo.value = nthCheck.default(pseudo.value)
       pseudo.valueType = 'function'
     }
   }