Changes to be used with ES6

.jshintrc

@@ -1,6 +1,7 @@
 // Based on jshint defaults: http://goo.gl/OpjUs
 
 {
+    "esversion": 6,
     // If the scan should stop on first error.
     "passfail": false,
     // Maximum errors before stopping.

README.md

@@ -59,6 +59,18 @@ Synchronously removes a pid file. Does not throw if the pid file is missing or
 if the removal fails. Returns a boolean indicating whether the pid file removal
 succeeded.
 
+#### npid.isRunning(pid): bool
+
+- pid: pid number
+
+Make a test if the pid process is still running
+
+#### npid.exists(path): bool
+
+- path: pid file path
+
+Synchronously evaluate is file already exists and pid process is still o execution
+
 ### Class Pid
 
 Represents a handle to a pid file and expose an API to remove it either
@@ -73,7 +85,7 @@ removal succeeded.
 
 #### pid.removeOnExit()
 
-Removes the pid file on normal process exit.
+Removes the pid file on normal process exit or if process got SIGTERM signal.
 
 ## License
 

lib/pid.js

@@ -3,57 +3,111 @@
  * Licensed under the MIT license.
  */
 
-var fs = require('fs');
+const fs = require('node:fs');
 
-/**
- * Pid file handle which can be used to remove the pid file.
- * @param path The pid file's path.
- */
-function Pid(path) {
-    this.path_ = path;
-}
+const actions = {
+    /**
+     * Check if the PID process is still running
+     *
+     * @param {String|Number} pid
+     * @returns {Boolean}
+     */
+    isRunning (pid) {
+        try {
+            return process.kill(pid, 0);
+        }
+        catch (e) {
+            return e.code === 'EPERM';
+        }
+    },
+    /**
+     * Check if PID file exists and is running
+     *
+     * @param {String} path
+     * @returns {Booelan}
+     */
+    exists (path) {
+        let result = false;
 
-/** Removes the PID file synchronously. Does not throw. */
-Pid.prototype.remove = function() {
-    return module.exports.remove(this.path_);
-};
+        try {
+            const st = fs.statSync(path);
 
-/** Removes the PID file on normal process exit. */
-Pid.prototype.removeOnExit = function() {
-    process.on('exit', this.remove.bind(this));
-};
+            if (st.isFile()) {
+                const pid = fs.readFileSync(path, {encoding: 'utf-8'});
 
-/**
- * Creates a pid file synchronously.
- * @param path Path to the pid file.
- * @param force Whether and existing pid file should be overwritten.
- */
-function create(path, force) {
-    var pid = new Buffer(process.pid + '\n');
-    var fd = fs.openSync(path, force ? 'w' : 'wx');
-    var offset = 0;
+                result = this.isRunning(pid);
+            }
+        } catch (err) {
+            result = true;
+        }
 
-    while (offset < pid.length) {
-        offset += fs.writeSync(fd, pid, offset, pid.length - offset);
-    }
+        return result;
+    },
+    /**
+     * Create a file PID
+     *
+     * @param {String} path
+     * @param {Booelan} force
+     */
+    create (path, force) {
+        const pid = Buffer.from(`${process.pid}\n`);
+        const fd = fs.openSync(path, force ? 'w' : 'wx');
+        let offset = 0;
 
-    fs.closeSync(fd);
+        while (offset < pid.length) {
+            offset += fs.writeSync(fd, pid, offset, pid.length - offset);
+        }
 
-    return new Pid(path);
-}
+        fs.closeSync(fd);
+
+        return new Pid(path);
+    },
+    /**
+     * Remove the pid file
+     *
+     * @param {String} path
+     * @return {Booelan}
+     */
+    remove (path) {
+        try {
+            fs.unlinkSync(path);
+            return true;
+        } catch (err) {
+            return false;
+        }
+    },
+    /**
+     * Terminate process linked in pid file
+     *
+     * @param {String} path
+     * @param {String|Number} signal
+     */
+    terminate (path, signal) {
+        const pid = fs.readFileSync(path, {encoding: 'utf-8'});
+
+        return process.kill(pid, signal);
+    }
+};
 
 /**
- * Removes a pid file synchronously. Does not throw.
+ * Pid file handle which can be used to remove the pid file.
+ *
  * @param path The pid file's path.
  */
-function remove(path) {
-    try {
-        fs.unlinkSync(path);
-        return true;
-    } catch (err) {
-        return false;
-    }
+function Pid (path) {
+    /** @var {String} path_ */
+    this.path_ = path;
+
+    /** Removes the PID file synchronously. Does not throw. */
+    this.remove = function () {
+        return actions.remove(this.path_);
+    };
+
+    /** Removes the PID file on normal process exit. */
+    this.removeOnExit = function() {
+        process.on('exit', this.remove.bind(this));
+        process.on('SIGTERM', this.remove.bind(this));
+    };
 }
 
-module.exports.create = create;
-module.exports.remove = remove;
+module.exports = actions;