[ESnext] Implement Promise.prototype.finally

test/mjsunit/harmony/promise-prototype-finally.js

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-promise-finally --allow-natives-syntax
+
+var asyncAssertsExpected = 0;
+
+function assertUnreachable() {
+  %AbortJS("Unreachable: failure");
+}
+
+function assertAsyncRan() {
+  ++asyncAssertsExpected;
+}
+
+function assertAsync(b, s) {
+  if (b) {
+    print(s, "succeeded");
+  } else {
+    %AbortJS(s + " FAILED!");
+  }
+  --asyncAssertsExpected;
+}
+
+function assertEqualsAsync(b, s) {
+  if (b === s) {
+    print(b, "===", s, "succeeded");
+  } else {
+    %AbortJS(b + "===" + s + " FAILED!");
+  }
+  --asyncAssertsExpected;
+}
+
+function assertAsyncDone(iteration) {
+  var iteration = iteration || 0;
+  %EnqueueMicrotask(function() {
+    if (asyncAssertsExpected === 0)
+      assertAsync(true, "all");
+    else if (
+      iteration > 10 // Shouldn't take more.
+    )
+      assertAsync(false, "all... " + asyncAssertsExpected);
+    else
+      assertAsyncDone(iteration + 1);
+  });
+}
+
+(function() {
+  assertThrows(
+    function() {
+      Promise.prototype.finally.call(5);
+    },
+    TypeError
+  );
+})();
+
+// resolve/finally/then
+(function() {
+  Promise.resolve(3).finally().then(
+    x => {
+      assertEqualsAsync(3, x);
+    },
+    assertUnreachable
+  );
+  assertAsyncRan();
+})();
+
+// reject/finally/then
+(function() {
+  Promise.reject(3).finally().then(assertUnreachable, x => {
+    assertEqualsAsync(3, x);
+  });
+  assertAsyncRan();
+})();
+
+// reject/finally/catch
+(function() {
+  Promise.reject(3).finally().catch(reason => {
+    assertEqualsAsync(3, reason);
+  });
+  assertAsyncRan();
+})();
+
+// reject/finally/then/catch
+(function() {
+  Promise.reject(3).finally().then(assertUnreachable).catch(reason => {
+    assertEqualsAsync(3, reason);
+  });
+  assertAsyncRan();
+})();
+
+// resolve/then/finally/then
+(function() {
+  Promise.resolve(3)
+    .then(x => {
+      assertEqualsAsync(3, x);
+      return x;
+    })
+    .finally()
+    .then(
+      x => {
+        assertEqualsAsync(3, x);
+      },
+      assertUnreachable
+    );
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/catch/finally/then
+(function() {
+  Promise.reject(3)
+    .catch(x => {
+      assertEqualsAsync(3, x);
+      return x;
+    })
+    .finally()
+    .then(
+      x => {
+        assertEqualsAsync(3, x);
+      },
+      assertUnreachable
+    );
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-throw/then
+(function() {
+  Promise.resolve(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 1;
+    })
+    .then(assertUnreachable, function onRejected(reason) {
+      assertEqualsAsync(1, reason);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-throw/then
+(function() {
+  Promise.reject(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 1;
+    })
+    .then(assertUnreachable, function onRejected(reason) {
+      assertEqualsAsync(1, reason);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-return/then
+(function() {
+  Promise.resolve(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return 4;
+    })
+    .then(
+      x => {
+        assertEqualsAsync(x, 3);
+      },
+      assertUnreachable
+    );
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-return/then
+(function() {
+  Promise.reject(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return 4;
+    })
+    .then(assertUnreachable, x => {
+      assertEqualsAsync(x, 3);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/catch-throw/finally-throw/then
+(function() {
+  Promise.reject(3)
+    .catch(e => {
+      assertEqualsAsync(3, e);
+      throw e;
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 4;
+    })
+    .then(assertUnreachable, function onRejected(e) {
+      assertEqualsAsync(4, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/then-throw/finally-throw/then
+(function() {
+  Promise.resolve(3)
+    .then(e => {
+      assertEqualsAsync(3, e);
+      throw e;
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 4;
+    })
+    .then(assertUnreachable, function onRejected(e) {
+      assertEqualsAsync(4, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-return-rejected-promise/then
+(function() {
+  Promise.resolve(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.reject(4);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(4, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-return-rejected-promise/then
+(function() {
+  Promise.reject(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.reject(4);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(4, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-return-resolved-promise/then
+(function() {
+  Promise.resolve(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.resolve(4);
+    })
+    .then(
+      x => {
+        assertEqualsAsync(3, x);
+      },
+      assertUnreachable
+    );
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-return-resolved-promise/then
+(function() {
+  Promise.reject(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.resolve(4);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(3, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-return-resolved-promise/then
+(function() {
+  Promise.reject(3)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.resolve(4);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(3, e);
+    });
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-thenable-resolve/then
+(function() {
+  var thenable = {
+    then: function(onResolve, onReject) {
+      onResolve(5);
+    }
+  };
+
+  Promise.resolve(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return thenable;
+    })
+    .then(
+      x => {
+        assertEqualsAsync(5, x);
+      },
+      assertUnreachable
+    );
+
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-thenable-resolve/then
+(function() {
+  var thenable = {
+    then: function(onResolve, onReject) {
+      onResolve(1);
+    }
+  };
+
+  Promise.reject(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return thenable;
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(5, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-thenable-reject/then
+(function() {
+  var thenable = {
+    then: function(onResolve, onReject) {
+      onReject(1);
+    }
+  };
+
+  Promise.reject(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return thenable;
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-thenable-reject/then
+(function() {
+  var thenable = {
+    then: function(onResolve, onReject) {
+      onReject(1);
+    }
+  };
+
+  Promise.resolve(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return thenable;
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally/finally/then
+(function() {
+  Promise.resolve(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(
+      x => {
+        assertEqualsAsync(5, x);
+      },
+      assertUnreachable
+    );
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-throw/finally/then
+(function() {
+  Promise.resolve(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 1;
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-return-rejected-promise/finally/then
+(function() {
+  Promise.resolve(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.reject(1);
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally/finally/then
+(function() {
+  Promise.reject(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(5, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-throw/finally/then
+(function() {
+  Promise.reject(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      throw 1;
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// reject/finally-return-rejected-promise/finally/then
+(function() {
+  Promise.reject(5)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return Promise.reject(1);
+    })
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(1, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+  assertAsyncRan();
+})();
+
+// resolve/finally-deferred-resolve/then
+(function() {
+  var resolve, reject;
+  var deferred = new Promise((x, y) => {
+    resolve = x;
+    reject = y;
+  });
+  Promise.resolve(1)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return deferred;
+    })
+    .then(
+      x => {
+        assertEqualsAsync(1, x);
+      },
+      assertUnreachable
+    );
+
+  assertAsyncRan();
+  assertAsyncRan();
+
+  resolve(5);
+})();
+
+// resolve/finally-deferred-reject/then
+(function() {
+  var resolve, reject;
+  var deferred = new Promise((x, y) => {
+    resolve = x;
+    reject = y;
+  });
+  Promise.resolve(1)
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+      return deferred;
+    })
+    .then(assertUnreachable, e => {
+      assertEqualsAsync(5, e);
+    });
+
+  assertAsyncRan();
+  assertAsyncRan();
+
+  reject(5);
+})();
+
+// all/finally/then
+(function() {
+  var resolve, reject;
+  var deferred = new Promise((x, y) => {
+    resolve = x;
+    reject = y;
+  });
+
+  Promise.all([deferred])
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(
+      ([x]) => {
+        assertEqualsAsync(1, x);
+      },
+      assertUnreachable
+    );
+
+  assertAsyncRan();
+  assertAsyncRan();
+
+  resolve(1);
+})();
+
+// race/finally/then
+(function() {
+  var resolve, reject;
+  var d1 = new Promise((x, y) => {
+    resolve = x;
+    reject = y;
+  });
+  var d2 = new Promise((x, y) => {
+    resolve = x;
+    reject = y;
+  });
+
+  Promise.race([d1, d2])
+    .finally(function onFinally() {
+      assertAsync(arguments.length === 0);
+    })
+    .then(
+      x => {
+        assertEqualsAsync(1, x);
+      },
+      assertUnreachable
+    );
+
+  assertAsyncRan();
+  assertAsyncRan();
+
+  resolve(1);
+})();
+
+var descriptor = Object.getOwnPropertyDescriptor(Promise.prototype, 'finally');
+assertTrue(descriptor.writable);
+assertTrue(descriptor.configurable);
+assertFalse(descriptor.enumerable);
+
+assertAsyncDone();