Use ESM

Author: wooorm

.gitignore

@@ -1,4 +1,3 @@
 .DS_Store
-.nyc_output/
-/node_modules/
+node_modules/
 coverage/

.prettierignore

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

index.js

@@ -1,14 +1,13 @@
-'use strict'
-
-var convert = require('unist-util-is/convert')
-
-module.exports = filter
+import {convert} from 'unist-util-is'
 
 var own = {}.hasOwnProperty
 
-function filter(tree, options, test) {
+export function filter(tree, options, test) {
   var is = convert(test || options)
-  var cascade = options.cascade == null ? true : options.cascade
+  var cascade =
+    options.cascade === undefined || options.cascade === null
+      ? true
+      : options.cascade
 
   return preorder(tree, null, null)
 

package.json

@@ -24,38 +24,35 @@
     "Titus Wormer <tituswormer@gmail.com> (https://wooorm.com)",
     "Christian Murphy <christian.murphy.42@gmail.com>"
   ],
+  "sideEffects": false,
+  "type": "module",
+  "main": "index.js",
+  "types": "types/index.d.ts",
   "files": [
     "index.js",
     "types/index.d.ts"
   ],
-  "types": "types/index.d.ts",
   "dependencies": {
-    "unist-util-is": "^4.0.0"
+    "unist-util-is": "^5.0.0"
   },
   "devDependencies": {
     "@types/mdast": "^3.0.0",
+    "c8": "^7.0.0",
     "dtslint": "^4.0.0",
-    "nyc": "^15.0.0",
     "prettier": "^2.0.0",
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
     "tape": "^5.0.0",
-    "unist-builder": "^2.0.0",
+    "unist-builder": "^3.0.0",
     "xo": "^0.38.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "test-api": "node test",
-    "test-coverage": "nyc --reporter lcov tape test.js",
-    "test-types": "dtslint types",
+    "test-api": "node test.js",
+    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
+    "test-types": "# dtslint types",
     "test": "npm run format && npm run test-coverage && npm run test-types"
   },
-  "nyc": {
-    "check-coverage": true,
-    "lines": 100,
-    "functions": 100,
-    "branches": 100
-  },
   "prettier": {
     "tabWidth": 2,
     "useTabs": false,
@@ -66,21 +63,11 @@
   },
   "xo": {
     "prettier": true,
-    "esnext": false,
     "rules": {
-      "eqeqeq": [
-        "error",
-        "always",
-        {
-          "null": "ignore"
-        }
-      ],
-      "no-eq-null": "off",
+      "no-var": "off",
+      "prefer-arrow-callback": "off",
       "unicorn/explicit-length-check": "off"
-    },
-    "ignores": [
-      "unist-util-position.js"
-    ]
+    }
   },
   "remarkConfig": {
     "plugins": [

readme.md

@@ -13,6 +13,9 @@ given test.
 
 ## 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
@@ -22,8 +25,8 @@ npm install unist-util-filter
 ## Use
 
 ```js
-var u = require('unist-builder')
-var filter = require('unist-util-filter')
+import {u} from 'unist-builder'
+import {filter} from 'unist-util-filter'
 
 var tree = u('root', [
   u('leaf', '1'),
@@ -50,6 +53,9 @@ Yields:
 
 ## API
 
+This package exports the following identifiers: `filter`.
+There is no default export.
+
 ### `filter(tree[, options][, test])`
 
 Create a new [tree][] consisting of copies of all nodes that pass `test`.

test.js

@@ -1,8 +1,6 @@
-'use strict'
-
-var test = require('tape')
-var u = require('unist-builder')
-var filter = require('.')
+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')])