HeadManager.test.mjs

// @ts-check

import { createElement as h } from "react";
import { renderToStaticMarkup } from "react-dom/server";
import {
  assertEquals,
  assertStrictEquals,
  assertThrows,
} from "std/testing/asserts.ts";

import HeadManager from "./HeadManager.mjs";

Deno.test("`HeadManager` constructor.", () => {
  const headManager = new HeadManager();

  assertStrictEquals(headManager instanceof EventTarget, true);
  assertEquals(headManager.managed, new Map());
  assertStrictEquals(typeof headManager.add, "function");
  assertStrictEquals(typeof headManager.remove, "function");
  assertStrictEquals(typeof headManager.getHeadContent, "function");
});

Deno.test(
  "`HeadManager` method `add` with argument 1 `key` not a string.",
  () => {
    const headManager = new HeadManager();

    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    assertThrows(
      () => {
        headManager.add(
          // @ts-expect-error Testing invalid.
          true,
          h("title", null, ""),
        );
      },
      TypeError,
      "Argument 1 `key` must be a string.",
    );
  },
);

Deno.test(
  "`HeadManager` method `add` with argument 2 `content` not specified.",
  () => {
    const headManager = new HeadManager();

    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    assertThrows(
      () => {
        headManager
          // @ts-expect-error Testing invalid.
          .add("a");
      },
      TypeError,
      "Argument 2 `content` must be specified.",
    );
  },
);

Deno.test(
  "`HeadManager` method `add` with argument 3 `priority` not a number.",
  () => {
    const headManager = new HeadManager();

    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    assertThrows(
      () => {
        headManager.add(
          "a",
          h("title", null, ""),
          // @ts-expect-error Testing invalid.
          true,
        );
      },
      TypeError,
      "Argument 3 `priority` must be a number.",
    );
  },
);

Deno.test("`HeadManager` method `add`, unpopulated, priority default.", () => {
  const headManager = new HeadManager();
  const key = "a";
  const content = h("title", null, "");

  /** @type {Array<Event>} */
  const events = [];

  headManager.addEventListener("update", (/** @type {Event} */ event) => {
    events.push(event);
    assertEquals(Array.from(headManager.managed.entries()), [
      [content, { key, priority: 0 }],
    ]);
  });

  headManager.add(key, content);

  assertStrictEquals(events.length, 1);
  assertStrictEquals(events[0] instanceof CustomEvent, true);
  assertStrictEquals(events[0].type, "update");
  assertStrictEquals(events[0].cancelable, false);
});

Deno.test(
  "`HeadManager` method `add`, unpopulated, priority specified.",
  () => {
    const headManager = new HeadManager();
    const key = "a";
    const content = h("title", null, "");
    const priority = 1;

    /** @type {Array<Event>} */
    const events = [];

    headManager.addEventListener("update", (/** @type {Event} */ event) => {
      events.push(event);
      assertEquals(Array.from(headManager.managed.entries()), [
        [content, { key, priority }],
      ]);
    });

    headManager.add(key, content, priority);

    assertStrictEquals(events.length, 1);
    assertStrictEquals(events[0] instanceof CustomEvent, true);
    assertStrictEquals(events[0].type, "update");
    assertStrictEquals(events[0].cancelable, false);
  },
);

Deno.test(
  "`HeadManager` method `add`, populated, keys same, content same, priorities same.",
  () => {
    const headManager = new HeadManager();
    const key = "a";
    const content = h("title", null, "");
    const priority = 1;

    headManager.add(key, content, priority);
    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    headManager.add(key, content, priority);

    assertEquals(Array.from(headManager.managed.entries()), [
      [content, { key, priority }],
    ]);
  },
);

Deno.test(
  "`HeadManager` method `add`, populated, keys different, content same, priorities same.",
  () => {
    const headManager = new HeadManager();
    const firstKey = "a";
    const content = h("title", null, "");
    const priority = 1;

    headManager.add(firstKey, content, priority);
    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    const secondKey = "b";

    assertThrows(
      () => {
        headManager.add(secondKey, content, priority);
      },
      TypeError,
      `Argument 2 \`content\` already added with a different \`key\` of \`${firstKey}\`.`,
    );

    assertEquals(Array.from(headManager.managed.entries()), [
      [content, { key: firstKey, priority }],
    ]);
  },
);

Deno.test(
  "`HeadManager` method `add`, populated, keys same, content same, priorities different.",
  () => {
    const headManager = new HeadManager();
    const key = "a";
    const content = h("title", null, "");
    const firstPriority = 1;

    headManager.add(key, content, firstPriority);
    headManager.addEventListener("update", () => {
      throw new Error("Unexpected `update` event.");
    });

    const secondPriority = 2;

    assertThrows(
      () => {
        headManager.add(key, content, secondPriority);
      },
      TypeError,
      `Argument 2 \`content\` already added with a different \`priority\` of \`${firstPriority}\`.`,
    );

    assertEquals(Array.from(headManager.managed.entries()), [
      [content, { key, priority: firstPriority }],
    ]);
  },
);

Deno.test("`HeadManager` method `add`, populated, content different.", () => {
  const headManager = new HeadManager();
  const firstKey = "a";
  const firstContent = h("title", null, "a");
  const secondKey = "b";
  const secondContent = h("meta", { name: "description", content: "b" });

  headManager.add(firstKey, firstContent);

  /** @type {Array<Event>} */
  const events = [];

  headManager.addEventListener("update", (/** @type {Event} */ event) => {
    events.push(event);
    assertEquals(Array.from(headManager.managed.entries()), [
      [
        firstContent,
        {
          key: firstKey,
          priority: 0,
        },
      ],
      [
        secondContent,
        {
          key: secondKey,
          priority: 0,
        },
      ],
    ]);
  });

  headManager.add(secondKey, secondContent);

  assertStrictEquals(events.length, 1);
  assertStrictEquals(events[0] instanceof CustomEvent, true);
  assertStrictEquals(events[0].type, "update");
  assertStrictEquals(events[0].cancelable, false);
});

Deno.test("`HeadManager` method `remove`, existing.", () => {
  const headManager = new HeadManager();
  const firstKey = "a";
  const firstContent = h("title", null, "a");
  const secondKey = "b";
  const secondContent = h("meta", { name: "description", content: "b" });

  headManager.add(firstKey, firstContent);
  headManager.add(secondKey, secondContent);

  /** @type {Array<Event>} */
  const events = [];

  headManager.addEventListener("update", (/** @type {Event} */ event) => {
    events.push(event);
    assertEquals(Array.from(headManager.managed.entries()), [
      [
        secondContent,
        {
          key: secondKey,
          priority: 0,
        },
      ],
    ]);
  });

  headManager.remove(firstContent);

  assertStrictEquals(events.length, 1);
  assertStrictEquals(events[0] instanceof CustomEvent, true);
  assertStrictEquals(events[0].type, "update");
  assertStrictEquals(events[0].cancelable, false);
});

Deno.test("`HeadManager` method `remove`, missing.", () => {
  const headManager = new HeadManager();

  headManager.addEventListener("update", () => {
    throw new Error("Unexpected `update` event.");
  });

  headManager.remove(h("title", null, ""));
});

Deno.test("`HeadManager` method `getHeadContent`, 1 added.", () => {
  const headManager = new HeadManager();
  const key = "a";

  headManager.add(key, h("title", null, "a"));

  assertEquals(
    renderToStaticMarkup(h("head", null, headManager.getHeadContent())),
    "<head><title>a</title></head>",
  );
});

Deno.test(
  "`HeadManager` method `getHeadContent`, 2 added, keys same, priority same.",
  () => {
    const headManager = new HeadManager();
    const key = "a";

    headManager.add(key, h("title", null, "a"));
    headManager.add(key, h("title", null, "b"));

    assertEquals(
      renderToStaticMarkup(h("head", null, headManager.getHeadContent())),
      "<head><title>b</title></head>",
    );
  },
);

Deno.test(
  "`HeadManager` method `getHeadContent`, 2 added, keys same, priority different.",
  () => {
    const headManager = new HeadManager();
    const key = "a";

    headManager.add(key, h("title", null, "a"), 2);
    headManager.add(key, h("title", null, "b"), 1);

    assertEquals(
      renderToStaticMarkup(h("head", null, headManager.getHeadContent())),
      "<head><title>a</title></head>",
    );
  },
);

Deno.test(
  "`HeadManager` method `getHeadContent`, 2 added, keys different.",
  () => {
    const headManager = new HeadManager();

    // To test sorting by key, add them out of order with their keys.
    headManager.add("b", h("meta", { name: "b", content: "b" }));
    headManager.add("a", h("meta", { name: "a", content: "a" }));

    assertEquals(
      renderToStaticMarkup(h("head", null, headManager.getHeadContent())),
      '<head><meta name="a" content="a"/><meta name="b" content="b"/></head>',
    );
  },
);