Fix duplicate point creation in polygon draw and add tests (#621)

Co-authored-by: Sumit Kumar <sk@outlook.com>

cypress/integration/polygon.spec.js

@@ -174,6 +174,43 @@ describe('Draw & Edit Poly', () => {
     cy.hasVertexMarkers(4);
   });
 
+  it('doesnt allow duplicate points in polygon', () => {
+    cy.toolbarButton('polygon').click();
+
+    cy.get(mapSelector)
+      .click(90, 250)
+      .click(100, 50)
+      .click(150, 50)
+      .dblclick(150, 150)
+      .click(90, 250);
+
+    cy.toolbarButton('edit').click();
+
+    cy.hasVertexMarkers(4);
+
+    cy.toolbarButton('edit').click();
+  });
+
+  it('doesnt break on dblclick while self intersection disabled', () => {
+    cy.window().then(({ map }) => {
+      map.pm.enableDraw('Polygon', {
+        allowSelfIntersection: false,
+      });
+    });
+
+    cy.get(mapSelector)
+      .click(90, 250)
+      .click(100, 50)
+      .click(150, 50)
+      .dblclick(150, 150)
+      .click(90, 250);
+
+    cy.toolbarButton('edit').click();
+
+    cy.hasVertexMarkers(4);
+
+    cy.toolbarButton('edit').click();
+  });
 
   it('prevent creation while self intersection', () => {
 

src/js/Draw/L.PM.Draw.Polygon.js

@@ -75,6 +75,11 @@ Draw.Polygon = Draw.Line.extend({
       if (this.options.snappable) {
         this._cleanupSnapping();
       }
+    } else {
+      // add a click event w/ no handler to the marker
+      // event won't bubble so prevents creation of identical markers in same polygon
+      // fixes issue where double click during poly creation when allowSelfIntersection: false caused it to break
+      marker.on('click', () => (1));
     }
 
     // handle tooltip text