Add typings

package.json

@@ -16,30 +16,37 @@
     "Titus Wormer <[email protected]> (https://wooorm.com)"
   ],
   "files": [
-    "index.js"
+    "index.js",
+    "types/index.d.ts"
   ],
+  "types": "types/index.d.ts",
   "dependencies": {
-    "unist-util-is": "^3.0.0"
+    "@types/unist": "^2.0.3",
+    "unist-util-is": "^4.0.0"
   },
   "devDependencies": {
     "browserify": "^16.0.0",
+    "dtslint": "^0.9.0",
     "nyc": "^14.0.0",
     "prettier": "^1.0.0",
     "remark": "^10.0.0",
     "remark-cli": "^6.0.0",
     "remark-preset-wooorm": "^5.0.0",
     "tape": "^4.0.0",
     "tinyify": "^2.0.0",
+    "typescript": "^3.5.3",
+    "unified": "^8.3.2",
     "xo": "^0.24.0"
   },
   "scripts": {
-    "format": "remark . -qfo && prettier --write \"**/*.js\" && xo --fix",
+    "format": "remark . -qfo && prettier --write \"**/*.{js,ts}\" && xo --fix",
     "build-bundle": "browserify index.js -s unistUtilVisitParents > unist-util-visit-parents.js",
     "build-mangle": "browserify index.js -s unistUtilVisitParents -p tinyify > unist-util-visit-parents.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"
+    "test-types": "dtslint types",
+    "test": "npm run format && npm run build && npm run test-coverage && npm run test-types"
   },
   "nyc": {
     "check-coverage": true,

types/index.d.ts

@@ -0,0 +1,111 @@
+// TypeScript Version: 3.5
+
+import {Node, Parent} from 'unist'
+import {Test} from 'unist-util-is'
+
+declare namespace visitParents {
+  /**
+   * Continue traversing as normal
+   */
+  type Continue = true
+
+  /**
+   * Do not traverse this node’s children
+   */
+  type Skip = 'skip'
+
+  /**
+   * Stop traversing immediately
+   */
+  type Exit = false
+
+  /**
+   * Union of the action types
+   */
+  type Action = Continue | Skip | Exit
+
+  /**
+   * List with one or two values, the first an action, the second an index.
+   */
+  type ActionTuple = [Action, Index]
+
+  /**
+   * Move to the sibling at index next (after node itself is completely traversed).
+   * Useful if mutating the tree, such as removing the node the visitor is currently on,
+   * or any of its previous siblings (or next siblings, in case of reverse)
+   * Results less than 0 or greater than or equal to children.length stop traversing the parent
+   */
+  type Index = number
+
+  /**
+   * Invoked when a node (matching test, if given) is found.
+   * Visitors are free to transform node.
+   * They can also transform the parent of node (the last of ancestors).
+   * Replacing node itself, if visit.SKIP is not returned, still causes its descendants to be visited.
+   * If adding or removing previous siblings (or next siblings, in case of reverse) of node,
+   * visitor should return a new index (number) to specify the sibling to traverse after node is traversed.
+   * Adding or removing next siblings of node (or previous siblings, in case of reverse)
+   * is handled as expected without needing to return a new index.
+   * Removing the children property of an ancestor still results in them being traversed.
+   *
+   * @param node Found node
+   * @param ancestors Ancestors of node
+   * @paramType V node type found
+   * @returns
+   * When Action is passed, treated as a tuple of [Action]
+   * When Index is passed, treated as a tuple of [CONTINUE, Index]
+   * When ActionTuple is passed,
+   *   Note that passing a tuple only makes sense if the action is SKIP.
+   *   If the action is EXIT, that action can be returned.
+   *   If the action is CONTINUE, index can be returned.
+   */
+  type Visitor<V extends Node> = (
+    node: V,
+    ancestors: Node[]
+  ) => void | Action | Index | ActionTuple
+}
+
+declare const visitParents: {
+  /**
+   * Visit children of tree which pass a test
+   *
+   * @param tree abstract syntax tree to visit
+   * @param test test node
+   * @param visitor function to run for each node
+   * @param reverse visit the tree in reverse, defaults to false
+   * @typeParam T tree node
+   * @typeParam V node type found
+   */
+  <V extends Node>(
+    tree: Node,
+    test: Test<V> | Array<Test<any>>,
+    visitor: visitParents.Visitor<V>,
+    reverse?: boolean
+  ): void
+
+  /**
+   * Visit children of a tree
+   *
+   * @param tree abstract syntax tree to visit
+   * @param visitor function to run for each node
+   * @param reverse visit the tree in reverse, defaults to false
+   */
+  (tree: Node, visitor: visitParents.Visitor<Node>, reverse?: boolean): void
+
+  /**
+   * Continue traversing as normal
+   */
+  CONTINUE: visitParents.Continue
+
+  /**
+   * Do not traverse this node’s children
+   */
+  SKIP: visitParents.Skip
+
+  /**
+   * Stop traversing immediately
+   */
+  EXIT: visitParents.Exit
+}
+
+export = visitParents

types/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "lib": ["es2015"],
+    "strict": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "strictNullChecks": true,
+    "strictFunctionTypes": true,
+    "baseUrl": ".",
+    "paths": {
+      "unist-util-visit-parents": ["index.d.ts"]
+    }
+  }
+}

types/tslint.json

@@ -0,0 +1,15 @@
+{
+  "extends": "dtslint/dtslint.json",
+  "rules": {
+    "callable-types": false,
+    "max-line-length": false,
+    "no-redundant-jsdoc": false,
+    "no-void-expression": false,
+    "only-arrow-functions": false,
+    "semicolon": false,
+    "unified-signatures": false,
+    "whitespace": false,
+    "interface-over-type-literal": false,
+    "no-unnecessary-generics": false
+  }
+}