Add more type definitions (#882)

* More typing to base.ts

* Add more types

* More types

pyscriptjs/tests/unit/utils.test.ts

@@ -0,0 +1,34 @@
+import { jest } from "@jest/globals"
+import { ensureUniqueId } from "../../src/utils"
+
+describe("Utils", () => {
+
+  let element: HTMLElement;
+
+  beforeEach(() => {
+    element = document.createElement("div");
+  })
+
+  it("ensureUniqueId sets unique id on element", async () => {
+    expect(element.id).toBe("")
+
+    ensureUniqueId(element)
+
+    expect(element.id).toBe("py-internal-0")
+  })
+
+  it("ensureUniqueId sets unique id with increasing counter", async () => {
+    const secondElement = document.createElement("div")
+
+    expect(element.id).toBe("")
+    expect(secondElement.id).toBe("")
+
+    ensureUniqueId(element)
+    ensureUniqueId(secondElement)
+
+    // The counter will have been incremented on
+    // the previous test, make sure it keeps increasing
+    expect(element.id).toBe("py-internal-1")
+    expect(secondElement.id).toBe("py-internal-2")
+  })
+})