Use ESM

Author: wooorm

.gitignore

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

.prettierignore

@@ -1,5 +1,2 @@
 coverage/
-nlcst-to-string.js
-nlcst-to-string.min.js
-*.json
 *.md

index.js

@@ -1,9 +1,5 @@
-'use strict'
-
-module.exports = nlcstToString
-
 // Stringify one nlcst node or list of nodes.
-function nlcstToString(node, separator = '') {
+export function toString(node, separator = '') {
   var values
   var length
   var children
@@ -27,7 +23,7 @@ function nlcstToString(node, separator = '') {
   values = []
 
   while (length--) {
-    values[length] = nlcstToString(children[length], separator)
+    values[length] = toString(children[length], separator)
   }
 
   return values.join(separator)

package.json

@@ -24,34 +24,26 @@
     "Titus Wormer <tituswormer@gmail.com> (https://wooorm.com)",
     "Kenichiro Murata <kenichiro.murata@gmail.com>"
   ],
+  "sideEffects": false,
+  "type": "module",
+  "main": "index.js",
   "files": [
     "index.js"
   ],
   "devDependencies": {
-    "browserify": "^17.0.0",
-    "nyc": "^15.0.0",
+    "c8": "^7.0.0",
     "prettier": "^2.0.0",
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
     "tape": "^5.0.0",
-    "tinyify": "^3.0.0",
-    "unist-builder": "^2.0.0",
+    "unist-builder": "^3.0.0",
     "xo": "^0.38.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "build-bundle": "browserify . -s nlcstToString -o nlcst-to-string.js",
-    "build-mangle": "browserify . -s nlcstToString -p tinyify -o nlcst-to-string.min.js",
-    "build": "npm run build-bundle && npm run build-mangle",
-    "test-api": "node test",
-    "test-coverage": "nyc --reporter lcov tape test.js",
-    "test": "npm run format && npm run build && npm run test-coverage"
-  },
-  "nyc": {
-    "check-coverage": true,
-    "lines": 100,
-    "functions": 100,
-    "branches": 100
+    "test-api": "node test.js",
+    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
+    "test": "npm run format && npm run test-coverage"
   },
   "prettier": {
     "tabWidth": 2,
@@ -63,10 +55,10 @@
   },
   "xo": {
     "prettier": true,
-    "esnext": false,
-    "ignore": [
-      "nlcst-to-string.js"
-    ]
+    "rules": {
+      "no-var": "off",
+      "prefer-arrow-callback": "off"
+    }
   },
   "remarkConfig": {
     "plugins": [

readme.md

@@ -12,6 +12,9 @@
 
 ## Install
 
+This package is [ESM only](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c):
+Node 12+ is needed to use it and it must be `import`ed instead of `require`d.
+
 [npm][]:
 
 ```sh
@@ -21,7 +24,7 @@ npm install nlcst-to-string
 ## Use
 
 ```js
-var toString = require('nlcst-to-string')
+import {toString} from 'nlcst-to-string'
 
 console.log(
   toString({
@@ -37,6 +40,9 @@ console.log(
 
 ## API
 
+This package exports the following identifiers: `toString`.
+There is no default export.
+
 ### `toString(node[, separator])`
 
 Stringify the given [nlcst][] node (or list of nodes).

test.js

@@ -1,8 +1,6 @@
-'use strict'
-
-var test = require('tape')
-var u = require('unist-builder')
-var toString = require('.')
+import test from 'tape'
+import {u} from 'unist-builder'
+import {toString} from './index.js'
 
 test('toString()', function (t) {
   t.throws(