meteor/packages/ecmascript/runtime-tests.js

Tinytest.add("ecmascript - runtime - template literals", (test) => {
  function dump(pieces) {
    var copy = {};
    // Can't use _.extend({}, pieces) because es5-shim adds enumerable
    // methods to Array.prototype, and _.extend has no own property check.
    _.each(_.keys(pieces), key => copy[key] = pieces[key]);
    return [copy, _.toArray(arguments).slice(1)];
  };
  const foo = 'B';
  // uses `babelHelpers.taggedTemplateLiteralLoose`
  test.equal(`\u0041${foo}C`, 'ABC');
  test.equal(dump`\u0041${foo}C`,
             [{0:'A', 1: 'C', raw: ['\\u0041', 'C']},
              ['B']]);
});

Tinytest.add("ecmascript - runtime - classes - basic", (test) => {
  {
    class Foo {
      constructor(x) {
        this.x = x;
      }
    }

    test.throws(() => {
      Foo(); // called without `new`
    });

    test.equal((new Foo(3)).x, 3);
  }

  {
    class Bar {
      constructor(x) {
        this.x = x;
      }
    }
    class Foo extends Bar {}

    test.throws(() => {
      Foo(); // called without `new`
    });

    test.equal((new Foo(3)).x, 3);
    test.isTrue((new Foo(3)) instanceof Foo);
    test.isTrue((new Foo(3)) instanceof Bar);
  }

  {
    class Foo {
      static staticMethod() {
        return 'classy';
      }

      prototypeMethod() {
        return 'prototypical';
      }
    }

    test.equal(Foo.staticMethod(), 'classy');
    test.equal((new Foo).prototypeMethod(), 'prototypical');
  }
});

Tinytest.add("ecmascript - runtime - classes - use before declare", (test) => {
  const x = function asdf() {};
  if (typeof asdf === 'function') {
    // We seem to be in IE 8, where function names leak into the enclosing
    // scope, contrary to the spec.  In this case, Babel does not (currently)
    // throw an error if you use a class before you declare it.  (Of course,
    // any other browser can tell the developer they screwed up!)
    test.expect_fail();
  }

  test.throws(() => {
    new Foo(); // use before definition
    class Foo {}
  });
});


Tinytest.add("ecmascript - runtime - classes - inheritance", (test) => {

  // uses `babelHelpers.inherits`
  {
    class Foo {
      static static1() {
        return 1;
      }
    }
    Foo.static2 = function () {
      return 2;
    };

    // static methods are inherited!
    class Bar extends Foo {}

    test.equal(Foo.static1(), 1);
    test.equal(Foo.static2(), 2);
    test.equal(Bar.static1(), 1);
    test.equal(Bar.static2(), 2);
  }

  {
    const buf = [];
    class Foo {
      constructor() {
        buf.push('hi');
      }
    }

    class Bar extends Foo {}

    new Bar();
    // derived class with no constructor gets a default constructor
    // that calls the super constructor
    test.equal(buf, ['hi']);
  }
});

Tinytest.add("ecmascript - runtime - classes - computed props", (test) => {
  {
    const frob = "inc";

    class Foo {
      static [frob](n) { return n+1; }
    }

    test.equal(Foo.inc(3), 4);
  }
});

if (Meteor.isServer) {
  // getters and setters don't work in all clients, but they should work
  // in classes on browsers that support them in the first place, and on
  // the server.  (Technically they just need a working
  // Object.defineProperty, found in IE9+ and all modern environments.)
  Tinytest.add("ecmascript - runtime - classes - getters/setters", (test) => {
    // uses `babelHelpers.createClass`
    class Foo {
      get two() { return 1+1; }
      static get three() { return 1+1+1; }
    }

    test.equal((new Foo).two, 2);
    test.equal(Foo.three, 3);
  });
}

Tinytest.add("ecmascript - runtime - block scope", (test) => {
  {
    const buf = [];
    const thunks = [];
    function print(x) {
      buf.push(x);
    };
    function doLater(f) {
      thunks.push(f);
    };

    for (let i = 0; i < 3; i++) {
      print(i);
    }
    test.equal(buf, [0, 1, 2]);
    buf.length = 0;

    for (let i = 0; i < 3; i++) {
      doLater(() => {
        print(i);
      });
    }

    _.each(thunks, f => f());
    test.equal(buf, [0, 1, 2]);
  }
});

Tinytest.add("ecmascript - runtime - classes - super", (test) => {
  {
    class Class1 {
      foo() { return 123; }
      static bar() { return 1; }
    }
    class Class2 extends Class1 {}
    class Class3 extends Class2 {
      foo() {
        return super.foo() + Class3.bar();
      }
    }

    test.equal((new Class3).foo(), 124);
  }

  {
    class Foo {
      constructor(value) { this.value = value; }
      x() { return this.value; }
    }

    class Bar extends Foo {
      constructor() { super(123); }
      x() { return super.x(); }
    }

    test.equal((new Bar).x(), 123);
  }
});

Tinytest.add("ecmascript - runtime - object rest/spread", (test) => {
  const middle = {b:2, c:3};
  // uses `babelHelpers._extends`
  const full = {a:1, ...middle, d:4};
  test.equal(full, {a:1, b:2, c:3, d:4});
});

Tinytest.add("ecmascript - runtime - spread args to new", (test) => {

  const Foo = function (one, two, three) {
    test.isTrue(this instanceof Foo);
    test.equal(one, 1);
    test.equal(two, 2);
    test.equal(three, 3);
    this.created = true;
  };

  const oneTwo = [1, 2];

  // uses `babelHelpers.bind`
  const foo = new Foo(...oneTwo, 3);
  test.isTrue(foo.created);
});

Tinytest.add("ecmascript - runtime - destructuring", (test) => {
  // uses `babelHelpers.objectWithoutProperties` and
  // `babelHelpers.objectDestructuringEmpty`

  const obj = {a:1, b:2};
  const {a, ...rest} = obj;
  test.equal(a, 1);
  test.equal(rest, {b:2});

  const {} = {};

  test.throws(() => {
    const {} = null;
  }, /Cannot destructure undefined/);
});

Tinytest.addAsync("ecmascript - runtime - misc support", (test, done) => {
  // Verify that the runtime was installed.
  test.equal(typeof babelHelpers, "object");

  class Base {
    constructor(...args) {
      this.sum = 0;
      args.forEach(arg => this.sum += arg);
    }

    static inherited() {
      return "inherited";
    }
  }

  class Derived extends Base {
    constructor() {
      super(1, 2, 3);
    }
  }

  // Check that static methods are inherited.
  test.equal(Derived.inherited(), "inherited");

  const d = new Derived();
  test.equal(d.sum, 6);

  const expectedError = new Error("expected");

  Promise.resolve("working").then(result => {
    test.equal(result, "working");
    throw expectedError;
  }).catch(error => {
    test.equal(error, expectedError);
    if (Meteor.isServer) {
      const Fiber = Npm.require("fibers");
      // Make sure the Promise polyfill runs callbacks in a Fiber.
      test.instanceOf(Fiber.current, Fiber);
    }
  }).then(done, error => test.exception(error));
});