Added Node#now() with test #598 (#605)

Adds convenient method to Node for accessing the current time.

added now() method to Node that returns current Time using the node's clock
added now() to node.d.ts
added test case to test-node.js

Fix #598

Author: wayneparrott

lib/node.js

@@ -626,6 +626,14 @@ class Node {
     return this._clock;
   }
 
+  /**
+   * Get the current time using the node's clock.
+   * @returns {Time} - The current time.
+   */
+  now() {
+    return this.getClock().now();
+  }
+
   /**
    * Get the list of published topics discovered by the provided node for the remote node name.
    * @param {string} nodeName - The name of the node.

test/test-node.js

@@ -14,6 +14,7 @@
 
 'use strict';
 
+const IsClose = require('is-close');
 const assert = require('assert');
 const rclnodejs = require('../index.js');
 const assertUtils = require('./utils.js');
@@ -365,6 +366,16 @@ describe('rcl node methods testing', function() {
     assert.strictEqual(clock.clockType, rclnodejs.ClockType.ROS_TIME);
   });
 
+  it('node.now', function() {
+    const time = node.now();
+    assert.ok(time);
+    assert.strictEqual(node.getClock().clockType, time.clockType);
+
+    const seconds = time.secondsAndNanoseconds.seconds;
+    const dateSeconds = Date.now() / 1000;
+    assert.ok(IsClose.isClose(seconds, dateSeconds, 1));
+  });
+
   it('node.getNodeNames', function() {
     var nodeNames = node.getNodeNames();
 

types/node.d.ts

@@ -173,8 +173,17 @@ declare module 'rclnodejs' {
      */
     getClock(): Clock;
 
+    /**
+     * Get the current time using the node's clock.
+     * 
+     * @returns The current time.
+     */
+    now(): Time;
+
     /**
      * Get the nodeOptions provided through the constructor.
+     * 
+     * @returns The nodeOptions.
      */
     options(): NodeOptions;