feat: add support for key-only label filters (set-based label selectors) (#40)

Author: jeff-mccoy

__mocks__/browser-or-node.ts

@@ -0,0 +1,8 @@
+// mock the browser-or-node module
+
+import { jest } from "@jest/globals";
+
+jest.mock("browser-or-node", () => ({
+  isBrowser: false,
+  isNode: true,
+}));

src/fluent/index.ts

@@ -54,7 +54,7 @@ export function K8s<T extends GenericClass, K extends KubernetesObject = Instanc
    * @inheritdoc
    * @see {@link K8sInit.WithLabel}
    */
-  function WithLabel(key: string, value: string) {
+  function WithLabel(key: string, value = "") {
     filters.labels = filters.labels || {};
     filters.labels[key] = value;
     return withFilters;

src/fluent/types.ts

@@ -128,16 +128,17 @@ export type K8sWithFilters<K extends KubernetesObject> = K8sFilteredActions<K> &
    * K8s(kind.Deployment)
    * .WithLabel("foo", "bar")
    * .WithLabel("baz", "qux")
+   * .WithLabel("quux")
    * .Delete(...)
    * ```
    *
-   * Will only delete the Deployment if it has the`foo=bar` and `baz=qux` labels.
+   * Will only delete the Deployment if it has the`foo=bar` and `baz=qux` labels and the `quux` label exists.
    *
    * @param key - the label key
    * @param value - the label value
    * @returns the fluent API
    */
-  WithLabel: (key: string, value: string) => K8sWithFilters<K>;
+  WithLabel: (key: string, value?: string) => K8sWithFilters<K>;
 };
 
 export type K8sInit<K extends KubernetesObject> = K8sWithFilters<K> &

src/fluent/utils.test.ts

@@ -21,6 +21,21 @@ describe("pathBuilder Function", () => {
     expect(() => pathBuilder("", model, filters)).toThrow("Kind not specified for Unknown");
   });
 
+  it("should generate a path with a set-based label selector", () => {
+    const filters: Filters = {
+      namespace: "default",
+      name: "mypod",
+      labels: { iamalabel: "" },
+    };
+    const result = pathBuilder(serverUrl, Pod, filters);
+    const expected = new URL(
+      "/api/v1/namespaces/default/pods/mypod?labelSelector=iamalabel",
+      serverUrl,
+    );
+
+    expect(result.toString()).toEqual(expected.toString());
+  });
+
   it("should generate a path for core group kinds (with custom filters)", () => {
     const filters: Filters = {
       namespace: "default",

src/fluent/utils.ts

@@ -73,7 +73,9 @@ export function pathBuilder<T extends GenericClass>(
   // Add label selectors to the query params
   if (filters.labels) {
     const labelSelector = Object.entries(filters.labels)
-      .map(([key, value]) => `${key}=${value}`)
+      // Exists set-based operators only include the key
+      // See https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#set-based-requirement
+      .map(([key, value]) => (value ? `${key}=${value}` : key))
       .join(",");
 
     url.searchParams.set("labelSelector", labelSelector);