feat(component): implement Sequential ujsx component

test/component/sequential.test.ts

@@ -0,0 +1,60 @@
+import { describe, it, expect } from "vitest";
+import { Sequential } from "@/component/index.js";
+import type { UElement, UNode } from "@alkdev/ujsx";
+
+describe("Sequential", () => {
+  it("produces a UElement with type 'sequential' and no props", () => {
+    const result = Sequential({ children: [] });
+    expect(result.type).toBe("sequential");
+    expect(result.props).toEqual({});
+    expect(result.children).toEqual([]);
+  });
+
+  it("produces a UElement with optional id prop", () => {
+    const result = Sequential({ id: "my-seq", children: [] });
+    expect(result.type).toBe("sequential");
+    expect(result.props).toEqual({ id: "my-seq" });
+    expect(result.children).toEqual([]);
+  });
+
+  it("passes children through", () => {
+    const child1: UElement = { type: "operation", props: { name: "a" }, children: [] };
+    const child2: UElement = { type: "operation", props: { name: "b" }, children: [] };
+    const result = Sequential({ children: [child1, child2] });
+    expect(result.type).toBe("sequential");
+    expect(result.children).toEqual([child1, child2]);
+  });
+
+  it("single child is valid (degenerate case)", () => {
+    const child: UElement = { type: "operation", props: { name: "only" }, children: [] };
+    const result = Sequential({ children: [child] });
+    expect(result.type).toBe("sequential");
+    expect(result.children).toEqual([child]);
+  });
+
+  it("accepts nested structural children", () => {
+    const nested: UNode = { type: "parallel", props: {}, children: [] };
+    const result = Sequential({ children: [nested] });
+    expect(result.children).toHaveLength(1);
+    expect((result.children[0] as UElement).type).toBe("parallel");
+  });
+
+  it("omits id from props when not provided", () => {
+    const result = Sequential({ children: [] });
+    expect(result.props).not.toHaveProperty("id");
+  });
+
+  it("is a valid UElement (has type, props, children)", () => {
+    const result = Sequential({ children: [] });
+    expect(result).toHaveProperty("type");
+    expect(result).toHaveProperty("props");
+    expect(result).toHaveProperty("children");
+    expect(typeof result.type).toBe("string");
+    expect(typeof result.props).toBe("object");
+    expect(Array.isArray(result.children)).toBe(true);
+  });
+
+  it("displayName is Sequential", () => {
+    expect(Sequential.displayName).toBe("Sequential");
+  });
+});