refactor(UrdfModel): Convert UrdfModel to TypeScript, replace loops with for-of, and improve type safety

Signed-off-by: Drew Hoener <[email protected]>

Author: drewhoener

src/urdf/UrdfModel.ts

@@ -4,94 +4,110 @@
  * @author Russell Toris - [email protected]
  */
 
+import { DOMParser, MIME_TYPE } from '@xmldom/xmldom';
 import UrdfMaterial from './UrdfMaterial.js';
 import UrdfLink from './UrdfLink.js';
 import UrdfJoint from './UrdfJoint.js';
-import { DOMParser, MIME_TYPE } from '@xmldom/xmldom';
+import { isElement } from './UrdfUtils.js';
 
 // See https://developer.mozilla.org/docs/XPathResult#Constants
-var XPATH_FIRST_ORDERED_NODE_TYPE = 9;
+// const XPATH_FIRST_ORDERED_NODE_TYPE = 9;
+
+export interface UrdfModelOptions {
+  /**
+   * The XML element to parse.
+   */
+  xml?: Element;
+  /**
+   * The XML element to parse as a string.
+   */
+  string: string;
+}
 
 /**
  * A URDF Model can be used to parse a given URDF into the appropriate elements.
  */
 export default class UrdfModel {
-  materials = {};
-  links = {};
-  joints = {};
-  /**
-   * @param {Object} options
-   * @param {Element | null} [options.xml] - The XML element to parse.
-   * @param {string} [options.string] - The XML element to parse as a string.
-   */
-  constructor(options) {
-    var xmlDoc = options.xml;
-    var string = options.string;
+
+  name: string | null;
+  materials: Record<string, UrdfMaterial> = {};
+  links: Record<string, UrdfLink> = {};
+  joints: Record<string, UrdfJoint> = {};
+
+  constructor({ xml, string }: UrdfModelOptions) {
+    let xmlDoc = xml;
 
     // Check if we are using a string or an XML element
     if (string) {
       // Parse the string
-      var parser = new DOMParser();
-      xmlDoc = parser.parseFromString(string, MIME_TYPE.XML_TEXT).documentElement;
+      xmlDoc = new DOMParser().parseFromString(string, MIME_TYPE.XML_TEXT).documentElement;
     }
+
     if (!xmlDoc) {
       throw new Error('No URDF document parsed!');
     }
 
-    // Initialize the model with the given XML node.
-    // Get the robot tag
-    var robotXml = xmlDoc;
-
     // Get the robot name
-    this.name = robotXml.getAttribute('name');
+    this.name = xmlDoc.getAttribute('name');
 
+    const childNodes = xmlDoc.childNodes;
     // Parse all the visual elements we need
-    for (var nodes = robotXml.childNodes, i = 0; i < nodes.length; i++) {
-      /** @type {Element} */
-      // @ts-expect-error -- unknown why this doesn't work properly.
-      var node = nodes[i];
-      if (node.tagName === 'material') {
-        var material = new UrdfMaterial({
-          xml: node
-        });
-        // Make sure this is unique
-        if (this.materials[material.name] !== void 0) {
+    for (const node of childNodes) {
+
+      // Safety check to make sure we're working with an element.
+      if (!isElement(node)) {
+        continue;
+      }
+
+      switch (node.tagName) {
+        case 'material': {
+          const material = new UrdfMaterial({ xml: node });
+          // Make sure this is unique
+          if (!Object.hasOwn(this.materials, material.name)) {
+            this.materials[material.name] = material;
+            break;
+          }
+
           if (this.materials[material.name].isLink()) {
             this.materials[material.name].assign(material);
           } else {
-            console.warn('Material ' + material.name + 'is not unique.');
+            console.warn(`Material ${material.name} is not unique.`);
           }
-        } else {
-          this.materials[material.name] = material;
+
+          break;
         }
-      } else if (node.tagName === 'link') {
-        var link = new UrdfLink({
-          xml: node
-        });
-        // Make sure this is unique
-        if (this.links[link.name] !== void 0) {
-          console.warn('Link ' + link.name + ' is not unique.');
-        } else {
+        case 'link': {
+          const link = new UrdfLink({ xml: node });
+          // Make sure this is unique
+          if (Object.hasOwn(this.links, link.name)) {
+            console.warn(`Link ${link.name} is not unique.`);
+            break;
+          }
+
           // Check for a material
-          for (var j = 0; j < link.visuals.length; j++) {
-            var mat = link.visuals[j].material;
-            if (mat !== null && mat.name) {
-              if (this.materials[mat.name] !== void 0) {
-                link.visuals[j].material = this.materials[mat.name];
-              } else {
-                this.materials[mat.name] = mat;
-              }
+          for (const item of link.visuals) {
+            const mat = item.material;
+            if (!mat?.name) {
+              continue;
+            }
+
+            if (Object.hasOwn(this.materials, mat.name)) {
+              item.material = this.materials[mat.name];
+            } else {
+              this.materials[mat.name] = mat;
             }
           }
 
           // Add the link
           this.links[link.name] = link;
+
+          break;
+        }
+        case 'joint': {
+          const joint = new UrdfJoint({ xml: node });
+          this.joints[joint.name] = joint;
+          break;
         }
-      } else if (node.tagName === 'joint') {
-        var joint = new UrdfJoint({
-          xml: node
-        });
-        this.joints[joint.name] = joint;
       }
     }
   }