fix

lib/Element.ts

@@ -1,5 +1,5 @@
 export class Element {
-  public name: string;
+  private _name = '';
   protected parent_name: string;
 
   public get full_name (): string {
@@ -8,14 +8,23 @@ export class Element {
     return this.name;
   }
 
+  public get name (): string {
+    return this._name;
+  }
+
+  public set name (val: string) {
+    const new_name = val.replace (/[^a-z0-9]/giu, '')
+      .replace (/^[0-9]+/iu, '');
+    if (new_name === '')
+      throw new Error ('invalid name specified');
+    this._name = new_name;
+  }
+
   public get parent (): string {
     return this.parent_name;
   }
 
   public constructor (name: string, parent = '') {
-    const regex = /^[a-z_][a-z_0-9]+$/iu;
-    if (!regex.test (name))
-      throw new Error ('invalid name specified');
     this.name = name;
     this.parent_name = parent;
   }

test/Node.ts

@@ -49,8 +49,18 @@ test ('serialize table', (t) => {
 });
 
 test ('adhere to naming convention', (t) => {
+  const n = new Node ('invalid.name', 'parent');
+  t.is (n.name, 'invalidname');
+});
+
+test ('throw on invalid name', (t) => {
   t.throws (() => {
-    const n = new Node ('invalid.name', 'parent');
+    const n = new Node ('564#+-.,/@', 'parent');
     return n.toString ();
   }, { message: 'invalid name specified' });
 });
+
+test ('leave numbers after the first letter', (t) => {
+  const n = new Node ('i123nvalid.name', 'parent');
+  t.is (n.name, 'i123nvalidname');
+});