Add typescript types

Thanks to @lenovouser
Ref #9

Author: simonepri

index.d.ts

@@ -0,0 +1,80 @@
+declare namespace PidTree {
+  export interface Options {
+    /**
+     * Include the provided PID in the list. Ignored if -1 is passed as PID.
+     * @default false
+     */
+    root?: boolean;
+  }
+
+  export interface AdvancedResult {
+    /**
+     * PID of the parent.
+     */
+    ppid: number;
+    /**
+     * PID
+     */
+    pid: number;
+  }
+
+  export type Result = number;
+}
+
+/**
+ * Get the list of children pids of the given pid.
+ * @param  pid A PID. If -1 will return all the pids.
+ * @param  callback Called when the list is ready.
+ */
+declare function pidtree(
+  pid: string | number,
+  callback: (error: Error | undefined, result: PidTree.Result[]) => void
+): void;
+
+/**
+ * Get the list of children pids of the given pid.
+ * @param  pid A PID. If -1 will return all the pids.
+ * @param  options Options object.
+ * @param  callback Called when the list is ready.
+ */
+declare function pidtree(
+  pid: string | number,
+  options: PidTree.Options,
+  callback: (error: Error | undefined, result: PidTree.Result[]) => void
+): void;
+
+/**
+ * Get the list of children pids of the given pid.
+ * @param  pid A PID. If -1 will return all the pids.
+ * @param  options Options object.
+ * @param  callback Called when the list is ready.
+ */
+declare function pidtree(
+  pid: string | number,
+  options: PidTree.Options & {advanced: true},
+  callback: (error: Error | undefined, result: PidTree.AdvancedResult[]) => void
+): void;
+
+/**
+ * Get the list of children pids of the given pid.
+ * @param  pid A PID. If -1 will return all the pids.
+ * @param  [options] Optional options object.
+ * @returns A promise containing the list.
+ */
+declare function pidtree(
+  pid: string | number,
+  options?: PidTree.Options
+): Promise<PidTree.Result[]>;
+
+/**
+ * Get the list of children pids of the given pid.
+ * @param  pid A PID. If -1 will return all the pids.
+ * @param  options Options object.
+ * @returns A promise containing the list.
+ */
+declare function pidtree(
+  pid: string | number,
+  options: PidTree.Options & {advanced: true}
+): Promise<PidTree.AdvancedResult[]>;
+
+export = pidtree;

index.test-d.ts

@@ -0,0 +1,14 @@
+import {expectType} from 'tsd';
+
+import pidtree = require('.');
+
+(async () => {
+  expectType<number[]>(await pidtree(1));
+  expectType<number[]>(await pidtree('1'));
+  expectType<Array<{ppid: number; pid: number}>>(
+    await pidtree(1, {advanced: true})
+  );
+  expectType<Array<{ppid: number; pid: number}>>(
+    await pidtree('1', {advanced: true})
+  );
+})();

package.json

@@ -28,13 +28,15 @@
     "processes"
   ],
   "main": "index.js",
+  "types": "index.d.ts",
   "bin": {
     "pidtree": "./bin/pidtree.js"
   },
   "files": [
     "bin",
     "lib",
-    "index.js"
+    "index.js",
+    "index.d.ts"
   ],
   "engines": {
     "node": ">=0.10"
@@ -45,6 +47,7 @@
     "release": "np",
     "lint": "xo",
     "test": "nyc ava -m \"!*benchmark*\"",
+    "types": "tsd",
     "bench": "ava -m \"*benchmark*\"",
     "coverage": "codecov"
   },
@@ -60,6 +63,7 @@
     "through": "^2.3.8",
     "time-span": "^2.0.0",
     "tree-kill": "^1.1.0",
+    "tsd": "^0.11.0",
     "xo": "~0.20.3"
   },
   "ava": {