more layout engines

lib/Edge.ts

@@ -17,6 +17,7 @@ export class Edge {
   // eslint-disable-next-line @typescript-eslint/naming-convention
   public toString (): string {
     const attributes = [];
+
     if (this.style)
       attributes.push ({ name: 'style', value: this.style.toString () });
     if (this.color)

lib/Element.ts

@@ -14,6 +14,7 @@ export class Element {
 
   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;

lib/GraphLayouts.ts

@@ -1,4 +1,10 @@
 export enum GraphLayouts {
-  neato= 'neato',
-  dot= 'dot'
+  neato = 'neato',
+  dot = 'dot',
+  circo = 'circo',
+  fdp = 'fdp',
+  sfdp = 'sfdp',
+  osage = 'osage',
+  twopi = 'twopi',
+  patchwork = 'patchwork'
 }

lib/Node.ts

@@ -20,6 +20,7 @@ export class Node extends Element {
 
     const mapped_columns = this.table_contents
       .map ((val) => `<td>${val.join ('</td><td>')}</td>`);
+
     return `<table>\n  <tr>${
       mapped_columns.join ('</tr>\n  <tr>')
     }</tr>\n</table>`;
@@ -28,6 +29,7 @@ export class Node extends Element {
   // eslint-disable-next-line @typescript-eslint/naming-convention
   public toString (): string {
     const attributes = [];
+
     if (this.label || this.is_table) {
       attributes.push ({
         name:  'label',
@@ -51,6 +53,7 @@ export class Node extends Element {
           '"',
           '"'
         ];
+
       return `${v.name}=${d[0]}${v.value}${d[1]}`;
     })
       .join (', ');