Refactor code-style

Author: wooorm

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true

.gitignore

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

.prettierignore

@@ -0,0 +1 @@
+coverage/

.travis.yml

@@ -2,3 +2,4 @@ language: node_js
 node_js:
   - lts/boron
   - node
+after_script: bash <(curl -s https://codecov.io/bash)

README.md

@@ -1,38 +1,52 @@
-'use strict';
+'use strict'
 
-var flatmap = require('flatmap'),
-    is = require('unist-util-is');
+var flatmap = require('flatmap')
+var is = require('unist-util-is')
 
+module.exports = filter
 
-module.exports = function (ast, opts, predicate) {
-  if (arguments.length == 2) {
-    predicate = opts;
-    opts = {};
+function filter(tree, opts, test) {
+  var cascade
+
+  if (!test) {
+    test = opts
+    opts = {}
   }
-  opts.cascade = opts.cascade || opts.cascade === undefined;
 
-  return (function preorder (node, index, parent) {
-    if (!is(predicate, node, index, parent)) {
-      return null;
+  cascade = opts.cascade
+  cascade = cascade === null || cascade === undefined ? true : cascade
+
+  return preorder(tree, null, null)
+
+  function preorder(node, index, parent) {
+    var next
+
+    if (!is(test, node, index, parent)) {
+      return null
     }
 
-    var newNode = Object.keys(node).reduce(function (acc, key) {
-      if (key != 'children') {
-        acc[key] = node[key];
-      }
-      return acc;
-    }, {});
+    next = Object.keys(node).reduce(reduce, {})
 
     if (node.children) {
-      newNode.children = flatmap(node.children, function (child, index) {
-        return preorder(child, index, node);
-      });
+      next.children = flatmap(node.children, map)
+
+      if (cascade && node.children.length !== 0 && next.children.length === 0) {
+        return null
+      }
+    }
+
+    return next
 
-      if (opts.cascade && !newNode.children.length && node.children.length) {
-        return null;
+    function reduce(acc, key) {
+      if (key !== 'children') {
+        acc[key] = node[key]
       }
+
+      return acc
     }
 
-    return newNode;
-  }(ast, null, null));
-};
+    function map(child, index) {
+      return preorder(child, index, node)
+    }
+  }
+}

index.js

@@ -29,11 +29,50 @@
     "unist-util-is": "^2.0.0"
   },
   "devDependencies": {
+    "nyc": "^12.0.1",
+    "prettier": "^1.13.3",
+    "remark-cli": "^5.0.0",
+    "remark-preset-wooorm": "^4.0.0",
     "tape": "^4.4.0",
     "unist-builder": "^1.0.0",
-    "unist-util-select": "^1.3.0"
+    "unist-util-select": "^1.3.0",
+    "xo": "^0.21.1"
   },
   "scripts": {
-    "test": "tape test/*.js"
+    "format": "remark . -qfo && prettier --write '**/*.js' && xo --fix",
+    "test-api": "node test",
+    "test-coverage": "nyc --reporter lcov tape test.js",
+    "test": "npm run format && npm run test-coverage"
+  },
+  "nyc": {
+    "check-coverage": true,
+    "lines": 100,
+    "functions": 100,
+    "branches": 100
+  },
+  "prettier": {
+    "tabWidth": 2,
+    "useTabs": false,
+    "singleQuote": true,
+    "bracketSpacing": false,
+    "semi": false,
+    "trailingComma": "none"
+  },
+  "xo": {
+    "prettier": true,
+    "esnext": false,
+    "rules": {
+      "guard-for-in": "off",
+      "no-var": "off",
+      "prefer-arrow-callback": "off"
+    },
+    "ignores": [
+      "unist-util-position.js"
+    ]
+  },
+  "remarkConfig": {
+    "plugins": [
+      "preset-wooorm"
+    ]
   }
 }

package.json

@@ -0,0 +1,100 @@
+# unist-util-filter [![Build Status][build-badge]][build-page] [![Coverage Status][coverage-badge]][coverage-page]
+
+Create a new [unist][] tree with all nodes that pass the given test.
+
+## Install
+
+```sh
+npm install unist-util-filter
+```
+
+## Usage
+
+```js
+var filter = require('unist-util-filter');
+
+var tree = {
+  type: 'root',
+  children: [
+    {type: 'leaf', value: '1'},
+    {
+      type: 'node',
+      children: [
+        {type: 'leaf', value: '2'},
+        {type: 'node', children: [{type: 'leaf', value: '3'}]}
+      ]
+    },
+    {type: 'leaf', value: '4'}
+  ]
+}
+
+console.log(filter(tree, node => node.type != 'leaf' || node.value % 2 == 0))
+```
+
+Yields:
+
+```js
+{
+  type: 'root',
+  children: [
+    {type: 'node', children: [{type: 'leaf', value: '2'}]},
+    {type: 'leaf', value: '4'}
+  ]
+}
+```
+
+## API
+
+### `filter(tree, [opts], test)`
+
+Creates a copy of `tree` consisting of all nodes that pass `test`.
+The tree is filtered in [preorder][].
+
+###### Parameters
+
+*   `tree` ([`Node?`][node])
+    — Tree to filter
+*   `opts.cascade` (`boolean`, default: `true`)
+    — Whether to drop parent nodes if they had children, but all their
+    children were filtered out
+*   `test`
+    — See [`unist-util-is`][is] for details
+
+###### Returns
+
+A new tree ([`Node?`][node]) with nodes for which `test` returned `true`.
+`null` is returned if `tree` itself didn’t pass the test, or is cascaded away.
+
+## Contribute
+
+See [`contributing.md` in `syntax-tree/unist`][contributing] for ways to get
+started.
+
+This organisation has a [Code of Conduct][coc].  By interacting with this
+repository, organisation, or community you agree to abide by its terms.
+
+## License
+
+[MIT][] © Eugene Sharygin
+
+[mit]: LICENSE
+
+[unist]: https://github.com/syntax-tree/unist
+
+[node]: https://github.com/syntax-tree/unist#node
+
+[is]: https://github.com/syntax-tree/unist-util-is
+
+[preorder]: https://en.wikipedia.org/wiki/Tree_traversal
+
+[build-page]: https://travis-ci.org/syntax-tree/unist-util-filter
+
+[build-badge]: https://travis-ci.org/syntax-tree/unist-util-filter.svg?branch=master
+
+[coverage-page]: https://codecov.io/github/syntax-tree/unist-util-filter?branch=master
+
+[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/unist-util-filter.svg?branch=master
+
+[contributing]: https://github.com/syntax-tree/unist/blob/master/contributing.md
+
+[coc]: https://github.com/syntax-tree/unist/blob/master/code-of-conduct.md