Use ESM

Author: wooorm

.gitignore

@@ -1,8 +1,5 @@
 .DS_Store
 *.log
-.nyc_output/
 coverage/
 node_modules/
-hast-util-to-html.js
-hast-util-to-html.min.js
 yarn.lock

.prettierignore

@@ -1,6 +1,2 @@
-.nyc_output/
 coverage/
-hast-util-to-html.js
-hast-util-to-html.min.js
-*.json
 *.md

index.js

@@ -1,2 +1 @@
-'use strict'
-module.exports = require('./lib')
+export {toHtml} from './lib/index.js'

lib/all.js

@@ -1,11 +1,7 @@
-'use strict'
-
-var one = require('./one')
-
-module.exports = all
+import {one} from './one.js'
 
 // Serialize all children of `parent`.
-function all(ctx, parent) {
+export function all(ctx, parent) {
   var results = []
   var children = (parent && parent.children) || []
   var index = -1

lib/comment.js

@@ -1,17 +1,20 @@
-'use strict'
+import {stringifyEntities} from 'stringify-entities'
 
-var xtend = require('xtend')
-var entities = require('stringify-entities')
-
-module.exports = serializeComment
-
-function serializeComment(ctx, node) {
+export function comment(ctx, node) {
   // See: <https://html.spec.whatwg.org/multipage/syntax.html#comments>
   return ctx.bogusComments
-    ? '<?' + entities(node.value, xtend(ctx.entities, {subset: ['>']})) + '>'
+    ? '<?' +
+        stringifyEntities(
+          node.value,
+          Object.assign({}, ctx.entities, {subset: ['>']})
+        ) +
+        '>'
     : '<!--' + node.value.replace(/^>|^->|<!--|-->|--!>|<!-$/g, encode) + '-->'
 
   function encode($0) {
-    return entities($0, xtend(ctx.entities, {subset: ['<', '>']}))
+    return stringifyEntities(
+      $0,
+      Object.assign({}, ctx.entities, {subset: ['<', '>']})
+    )
   }
 }

lib/constants.js

@@ -1,10 +1,8 @@
-'use strict'
-
 // Maps of subsets.
 // Each value is a matrix of tuples.
 // The first value causes parse errors, the second is valid.
 // Of both values, the first value is unsafe, and the second is safe.
-module.exports = {
+export const constants = {
   // See: <https://html.spec.whatwg.org/#attribute-name-state>.
   name: [
     ['\t\n\f\r &/=>'.split(''), '\t\n\f\r "&\'/=>`'.split('')],

lib/doctype.js

@@ -1,25 +1,20 @@
-'use strict'
+import {ccount} from 'ccount'
+import {stringifyEntities} from 'stringify-entities'
 
-var xtend = require('xtend')
-var ccount = require('ccount')
-var entities = require('stringify-entities')
-
-module.exports = serializeDoctype
-
-function serializeDoctype(ctx, node) {
+export function doctype(ctx, node) {
   var sep = ctx.tightDoctype ? '' : ' '
   var parts = ['<!' + (ctx.upperDoctype ? 'DOCTYPE' : 'doctype')]
 
   if (node.name) {
     parts.push(sep, node.name)
 
-    if (node.public != null) {
+    if (node.public !== undefined && node.public !== null) {
       parts.push(' public', sep, quote(ctx, node.public))
-    } else if (node.system != null) {
+    } else if (node.system !== undefined && node.system !== null) {
       parts.push(' system')
     }
 
-    if (node.system != null) {
+    if (node.system !== undefined && node.system !== null) {
       parts.push(sep, quote(ctx, node.system))
     }
   }
@@ -36,7 +31,10 @@ function quote(ctx, value) {
 
   return (
     quote +
-    entities(string, xtend(ctx.entities, {subset: ['<', '&', quote]})) +
+    stringifyEntities(
+      string,
+      Object.assign({}, ctx.entities, {subset: ['<', '&', quote]})
+    ) +
     quote
   )
 }

lib/element.js

@@ -1,25 +1,20 @@
-'use strict'
-
-var xtend = require('xtend')
-var svg = require('property-information/svg')
-var find = require('property-information/find')
-var spaces = require('space-separated-tokens')
-var commas = require('comma-separated-tokens')
-var entities = require('stringify-entities')
-var ccount = require('ccount')
-var all = require('./all')
-var constants = require('./constants')
-
-module.exports = serializeElement
-
-function serializeElement(ctx, node, index, parent) {
+import {svg, find} from 'property-information'
+import {stringify as spaces} from 'space-separated-tokens'
+import {stringify as commas} from 'comma-separated-tokens'
+import {stringifyEntities} from 'stringify-entities'
+import {ccount} from 'ccount'
+import {all} from './all.js'
+import {constants} from './constants.js'
+
+// eslint-disable-next-line complexity
+export function element(ctx, node, index, parent) {
   var schema = ctx.schema
   var omit = schema.space === 'svg' ? false : ctx.omit
   var parts = []
   var selfClosing =
     schema.space === 'svg'
       ? ctx.closeEmpty
-      : ctx.voids.indexOf(node.tagName.toLowerCase()) > -1
+      : ctx.voids.includes(node.tagName.toLowerCase())
   var attrs
   var content
   var last
@@ -79,7 +74,7 @@ function serializeAttributes(ctx, props) {
   var last
 
   for (key in props) {
-    if (props[key] != null) {
+    if (props[key] !== undefined && props[key] !== null) {
       value = serializeAttribute(ctx, key, props[key])
       if (value) values.push(value)
     }
@@ -97,6 +92,7 @@ function serializeAttributes(ctx, props) {
   return values.join('')
 }
 
+// eslint-disable-next-line complexity
 function serializeAttribute(ctx, key, value) {
   var info = find(ctx.schema, key)
   var quote = ctx.quote
@@ -113,16 +109,17 @@ function serializeAttribute(ctx, key, value) {
   }
 
   if (
-    value == null ||
+    value === undefined ||
+    value === null ||
     value === false ||
-    (typeof value === 'number' && value !== value)
+    (typeof value === 'number' && Number.isNaN(value))
   ) {
     return ''
   }
 
-  name = entities(
+  name = stringifyEntities(
     info.attribute,
-    xtend(ctx.entities, {
+    Object.assign({}, ctx.entities, {
       // Always encode without parse errors in non-HTML.
       subset:
         constants.name[ctx.schema.space === 'html' ? ctx.valid : 1][ctx.safe]
@@ -152,7 +149,7 @@ function serializeAttribute(ctx, key, value) {
     typeof value === 'object' && 'length' in value
       ? // `spaces` doesn’t accept a second argument, but it’s given here just to
         // keep the code cleaner.
-        (info.commaSeparated ? commas.stringify : spaces.stringify)(value, {
+        (info.commaSeparated ? commas : spaces)(value, {
           padLeft: !ctx.tightLists
         })
       : String(value)
@@ -161,9 +158,9 @@ function serializeAttribute(ctx, key, value) {
 
   // Check unquoted value.
   if (ctx.unquoted) {
-    result = entities(
+    result = stringifyEntities(
       value,
-      xtend(ctx.entities, {
+      Object.assign({}, ctx.entities, {
         subset: constants.unquoted[ctx.valid][ctx.safe],
         attribute: true
       })
@@ -180,9 +177,9 @@ function serializeAttribute(ctx, key, value) {
 
     result =
       quote +
-      entities(
+      stringifyEntities(
         value,
-        xtend(ctx.entities, {
+        Object.assign({}, ctx.entities, {
           // Always encode without parse errors in non-HTML.
           subset: (quote === "'" ? constants.single : constants.double)[
             ctx.schema.space === 'html' ? ctx.valid : 1

lib/index.js

@@ -1,16 +1,9 @@
-'use strict'
+import {html, svg} from 'property-information'
+import {htmlVoidElements} from 'html-void-elements'
+import {omission} from './omission/index.js'
+import {one} from './one.js'
 
-var html = require('property-information/html')
-var svg = require('property-information/svg')
-var voids = require('html-void-elements')
-var omission = require('./omission')
-var one = require('./one')
-
-module.exports = toHtml
-
-var deprecationWarningIssued
-
-function toHtml(node, options) {
+export function toHtml(node, options) {
   var settings = options || {}
   var quote = settings.quote || '"'
   var alternative = quote === '"' ? "'" : '"'
@@ -19,21 +12,14 @@ function toHtml(node, options) {
     throw new Error('Invalid quote `' + quote + '`, expected `\'` or `"`')
   }
 
-  if ('allowDangerousHTML' in settings && !deprecationWarningIssued) {
-    deprecationWarningIssued = true
-    console.warn(
-      'Deprecation warning: `allowDangerousHTML` is a nonstandard option, use `allowDangerousHtml` instead'
-    )
-  }
-
   return one(
     {
       valid: settings.allowParseErrors ? 0 : 1,
       safe: settings.allowDangerousCharacters ? 0 : 1,
       schema: settings.space === 'svg' ? svg : html,
       omit: settings.omitOptionalTags && omission,
-      quote: quote,
-      alternative: alternative,
+      quote,
+      alternative,
       smart: settings.quoteSmart,
       unquoted: settings.preferUnquoted,
       tight: settings.tightAttributes,
@@ -44,7 +30,7 @@ function toHtml(node, options) {
       tightClose: settings.tightSelfClosing,
       collapseEmpty: settings.collapseEmptyAttributes,
       dangerous: settings.allowDangerousHtml || settings.allowDangerousHTML,
-      voids: settings.voids || voids.concat(),
+      voids: settings.voids || htmlVoidElements.concat(),
       entities: settings.entities || {},
       close: settings.closeSelfClosing,
       closeEmpty: settings.closeEmptyElements