Merge branch 'nk/minor-tweak' into 'master'

Return null when gl context not available instead of crashing

See merge request arction/lcjs/lcjs-headless!2

src/index.ts

@@ -33,6 +33,9 @@ dom.window.HTMLCanvasElement.prototype.getContext = function () {
     if (arguments[0] === 'webgl') {
         // create headless-gl GL context
         const ctx: ReturnType<typeof createContext> & Partial<StackGlResize> = createContext(1, 1, arguments[1])
+        if (!ctx) {
+            return ctx
+        }
         // insert the resize method to the context so that lcjs package can use it
         ctx.resize = ctx.getExtension('STACKGL_resize_drawingbuffer').resize
         return ctx