this causes an error when you attempt to extend it.
edit: add stack trace
edit2: leaflet specifically is calling Object.freeze on a number of things.
Uncaught TypeError: Cannot add property setStyle, object is not extensible
at Object.extend (leaflet-src.js:27)
at leaflet-dvf.js:2726
at Object.t.defaultRadius (leaflet-dvf.js:4472)
at __webpack_require__ (bootstrap e5cb412…:52)
at Object.68 (main.bundle.js:5553)
at __webpack_require__ (bootstrap e5cb412…:52)
at Object.333 (bs-tooltip.directive.ts:6)
at __webpack_require__ (bootstrap e5cb412…:52)
at Object.331 (app.component.ts:9)
at __webpack_require__ (bootstrap e5cb412…:52)
this causes an error when you attempt to extend it. edit: add stack trace edit2: leaflet specifically is calling Object.freeze on a number of things.