denoland-deno/std/node/_util/_util_callbackify_test.ts

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
//
// Adapted from Node.js. Copyright Joyent, Inc. and other Node contributors.
//
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// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
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// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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/* eslint-disable @typescript-eslint/no-explicit-any */

const { test } = Deno;
import { assert, assertStrictEquals } from "../../testing/asserts.ts";
import { callbackify } from "./_util_callbackify.ts";

const values = [
  "hello world",
  null,
  undefined,
  false,
  0,
  {},
  { key: "value" },
  Symbol("I am a symbol"),
  function ok(): void {},
  ["array", "with", 4, "values"],
  new Error("boo"),
];

class TestQueue {
  #waitingPromise: Promise<void>;
  #resolve?: () => void;
  #reject?: (err: unknown) => void;
  #queueSize = 0;

  constructor() {
    this.#waitingPromise = new Promise((resolve, reject) => {
      this.#resolve = resolve;
      this.#reject = reject;
    });
  }

  enqueue(fn: (done: () => void) => void): void {
    this.#queueSize++;
    try {
      fn(() => {
        this.#queueSize--;
        if (this.#queueSize === 0) {
          assert(
            this.#resolve,
            "Test setup error; async queue is missing #resolve"
          );
          this.#resolve();
        }
      });
    } catch (err) {
      assert(this.#reject, "Test setup error; async queue is missing #reject");
      this.#reject(err);
    }
  }

  waitForCompletion(): Promise<void> {
    return this.#waitingPromise;
  }
}

test("callbackify passes the resolution value as the second argument to the callback", async () => {
  const testQueue = new TestQueue();

  for (const value of values) {
    // eslint-disable-next-line require-await
    async function asyncFn(): Promise<typeof value> {
      return value;
    }
    const cbAsyncFn = callbackify(asyncFn);
    testQueue.enqueue((done) => {
      cbAsyncFn((err: unknown, ret: unknown) => {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        done();
      });
    });

    function promiseFn(): Promise<typeof value> {
      return Promise.resolve(value);
    }
    const cbPromiseFn = callbackify(promiseFn);
    testQueue.enqueue((done) => {
      cbPromiseFn((err: unknown, ret: unknown) => {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        done();
      });
    });

    function thenableFn(): PromiseLike<any> {
      return {
        then(onfulfilled): PromiseLike<any> {
          assert(onfulfilled);
          onfulfilled(value);
          return this;
        },
      };
    }
    const cbThenableFn = callbackify(thenableFn);
    testQueue.enqueue((done) => {
      cbThenableFn((err: unknown, ret: unknown) => {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        done();
      });
    });
  }

  await testQueue.waitForCompletion();
});

test("callbackify passes the rejection value as the first argument to the callback", async () => {
  const testQueue = new TestQueue();

  for (const value of values) {
    // eslint-disable-next-line require-await
    async function asyncFn(): Promise<never> {
      return Promise.reject(value);
    }
    const cbAsyncFn = callbackify(asyncFn);
    assertStrictEquals(cbAsyncFn.length, 1);
    assertStrictEquals(cbAsyncFn.name, "asyncFnCallbackified");
    testQueue.enqueue((done) => {
      cbAsyncFn((err: unknown, ret: unknown) => {
        assertStrictEquals(ret, undefined);
        if (err instanceof Error) {
          if ("reason" in err) {
            assert(!value);
            assertStrictEquals((err as any).code, "ERR_FALSY_VALUE_REJECTION");
            assertStrictEquals((err as any).reason, value);
          } else {
            assertStrictEquals(String(value).endsWith(err.message), true);
          }
        } else {
          assertStrictEquals(err, value);
        }
        done();
      });
    });

    function promiseFn(): Promise<never> {
      return Promise.reject(value);
    }
    const obj = {};
    Object.defineProperty(promiseFn, "name", {
      value: obj,
      writable: false,
      enumerable: false,
      configurable: true,
    });

    const cbPromiseFn = callbackify(promiseFn);
    assertStrictEquals(promiseFn.name, obj);
    testQueue.enqueue((done) => {
      cbPromiseFn((err: unknown, ret: unknown) => {
        assertStrictEquals(ret, undefined);
        if (err instanceof Error) {
          if ("reason" in err) {
            assert(!value);
            assertStrictEquals((err as any).code, "ERR_FALSY_VALUE_REJECTION");
            assertStrictEquals((err as any).reason, value);
          } else {
            assertStrictEquals(String(value).endsWith(err.message), true);
          }
        } else {
          assertStrictEquals(err, value);
        }
        done();
      });
    });

    function thenableFn(): PromiseLike<never> {
      return {
        then(onfulfilled, onrejected): PromiseLike<never> {
          assert(onrejected);
          onrejected(value);
          return this;
        },
      };
    }

    const cbThenableFn = callbackify(thenableFn);
    testQueue.enqueue((done) => {
      cbThenableFn((err: unknown, ret: unknown) => {
        assertStrictEquals(ret, undefined);
        if (err instanceof Error) {
          if ("reason" in err) {
            assert(!value);
            assertStrictEquals((err as any).code, "ERR_FALSY_VALUE_REJECTION");
            assertStrictEquals((err as any).reason, value);
          } else {
            assertStrictEquals(String(value).endsWith(err.message), true);
          }
        } else {
          assertStrictEquals(err, value);
        }
        done();
      });
    });
  }

  await testQueue.waitForCompletion();
});

test("callbackify passes arguments to the original", async () => {
  const testQueue = new TestQueue();

  for (const value of values) {
    // eslint-disable-next-line require-await
    async function asyncFn<T>(arg: T): Promise<T> {
      assertStrictEquals(arg, value);
      return arg;
    }

    const cbAsyncFn = callbackify(asyncFn);
    assertStrictEquals(cbAsyncFn.length, 2);
    assert(Object.getPrototypeOf(cbAsyncFn) !== Object.getPrototypeOf(asyncFn));
    assertStrictEquals(Object.getPrototypeOf(cbAsyncFn), Function.prototype);
    testQueue.enqueue((done) => {
      cbAsyncFn(value, (err: unknown, ret: unknown) => {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        done();
      });
    });

    function promiseFn<T>(arg: T): Promise<T> {
      assertStrictEquals(arg, value);
      return Promise.resolve(arg);
    }
    const obj = {};
    Object.defineProperty(promiseFn, "length", {
      value: obj,
      writable: false,
      enumerable: false,
      configurable: true,
    });

    const cbPromiseFn = callbackify(promiseFn);
    assertStrictEquals(promiseFn.length, obj);
    testQueue.enqueue((done) => {
      cbPromiseFn(value, (err: unknown, ret: unknown) => {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        done();
      });
    });
  }

  await testQueue.waitForCompletion();
});

test("callbackify preserves the `this` binding", async () => {
  const testQueue = new TestQueue();

  for (const value of values) {
    const objectWithSyncFunction = {
      fn(this: unknown, arg: typeof value): Promise<typeof value> {
        assertStrictEquals(this, objectWithSyncFunction);
        return Promise.resolve(arg);
      },
    };
    const cbSyncFunction = callbackify(objectWithSyncFunction.fn);
    testQueue.enqueue((done) => {
      cbSyncFunction.call(objectWithSyncFunction, value, function (
        this: unknown,
        err: unknown,
        ret: unknown
      ) {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        assertStrictEquals(this, objectWithSyncFunction);
        done();
      });
    });

    const objectWithAsyncFunction = {
      // eslint-disable-next-line require-await
      async fn(this: unknown, arg: typeof value): Promise<typeof value> {
        assertStrictEquals(this, objectWithAsyncFunction);
        return arg;
      },
    };
    const cbAsyncFunction = callbackify(objectWithAsyncFunction.fn);
    testQueue.enqueue((done) => {
      cbAsyncFunction.call(objectWithAsyncFunction, value, function (
        this: unknown,
        err: unknown,
        ret: unknown
      ) {
        assertStrictEquals(err, null);
        assertStrictEquals(ret, value);
        assertStrictEquals(this, objectWithAsyncFunction);
        done();
      });
    });
  }

  await testQueue.waitForCompletion();
});

test("callbackify throws with non-function inputs", () => {
  ["foo", null, undefined, false, 0, {}, Symbol(), []].forEach((value) => {
    try {
      callbackify(value as any);
      throw Error("We should never reach this error");
    } catch (err) {
      assert(err instanceof TypeError);
      assertStrictEquals((err as any).code, "ERR_INVALID_ARG_TYPE");
      assertStrictEquals(err.name, "TypeError");
      assertStrictEquals(
        err.message,
        'The "original" argument must be of type function.'
      );
    }
  });
});

test("callbackify returns a function that throws if the last argument is not a function", () => {
  // eslint-disable-next-line require-await
  async function asyncFn(): Promise<number> {
    return 42;
  }

  const cb = callbackify(asyncFn) as any;
  const args: unknown[] = [];

  ["foo", null, undefined, false, 0, {}, Symbol(), []].forEach((value) => {
    args.push(value);

    try {
      cb(...args);
      throw Error("We should never reach this error");
    } catch (err) {
      assert(err instanceof TypeError);
      assertStrictEquals((err as any).code, "ERR_INVALID_ARG_TYPE");
      assertStrictEquals(err.name, "TypeError");
      assertStrictEquals(
        err.message,
        "The last argument must be of type function."
      );
    }
  });
});