sebastienros.jint/Jint.Tests/Runtime/FunctionTests.cs

using Jint.Native;
using Jint.Native.Function;
using Jint.Runtime;
using Jint.Runtime.Interop;

namespace Jint.Tests.Runtime;

public class FunctionTests
{
    private readonly Engine _engine;

    public FunctionTests()
    {
        _engine = new Engine()
            .SetValue("equal", new Action<object, object>(Assert.Equal));
    }

    [Fact]
    public void BindCombinesBoundArgumentsToCallArgumentsCorrectly()
    {
        _engine.Evaluate("var testFunc = function (a, b, c) { return a + ', ' + b + ', ' + c + ', ' + JSON.stringify(arguments); }");

        Assert.Equal("a, 1, a, {\"0\":\"a\",\"1\":1,\"2\":\"a\"}", _engine.Evaluate("testFunc('a', 1, 'a');").AsString());
        Assert.Equal("a, 1, a, {\"0\":\"a\",\"1\":1,\"2\":\"a\"}", _engine.Evaluate("testFunc.bind('anything')('a', 1, 'a');").AsString());
    }

    [Fact]
    public void ArrowFunctionShouldBeExtensible()
    {
        new Engine()
            .SetValue("assert", new Action<bool>(Assert.True))
            .Execute(@"
                    var a = () => null
                    Object.defineProperty(a, 'hello', { enumerable: true, get: () => 'world' })
                    assert(a.hello === 'world')

                    a.foo = 'bar';
                    assert(a.foo === 'bar');
                ");
    }

    [Fact]
    public void BlockScopeFunctionShouldWork()
    {
        const string Script = @"
function execute(doc, args){
    var i = doc;
    {
        function doSomething() {
            return 'ayende';
        }

        i.Name = doSomething();
    }
}
";

        var engine = new Engine(options =>
        {
            options.Strict();
        });
        engine.Execute(Script);

        var obj = engine.Evaluate("var obj = {}; execute(obj); return obj;").AsObject();

        Assert.Equal("ayende", obj.Get("Name").AsString());
    }

    [Fact]
    public void ObjectCoercibleForCallable()
    {
        const string Script = @"
var booleanCount = 0;
Boolean.prototype.then = function() {
  booleanCount += 1;
};
function test() {
    this.then();    
}
testFunction.call(true);
assertEqual(booleanCount, 1);
";
        var engine = new Engine();
        engine
            .SetValue("testFunction", new ClrFunction(engine, "testFunction", (thisValue, args) =>
            {
                return engine.Invoke(thisValue, "then", new[] { JsValue.Undefined, args.At(0) });
            }))
            .SetValue("assertEqual", new Action<object, object>((a, b) => Assert.Equal(b, a)))
            .Execute(Script);
    }

    [Fact]
    public void AnonymousLambdaShouldHaveNameDefined()
    {
        Assert.True(_engine.Evaluate("(()=>{}).hasOwnProperty('name')").AsBoolean());
    }

    [Fact]
    public void CanInvokeConstructorsFromEngine()
    {
        _engine.Evaluate("class TestClass { constructor(a, b) { this.a = a; this.b = b; }}");
        _engine.Evaluate("function TestFunction(a, b) { this.a = a; this.b = b; }");

        var instanceFromClass = _engine.Construct("TestClass", "abc", 123).AsObject();
        Assert.Equal("abc", instanceFromClass.Get("a"));
        Assert.Equal(123, instanceFromClass.Get("b"));

        var instanceFromFunction = _engine.Construct("TestFunction", "abc", 123).AsObject();
        Assert.Equal("abc", instanceFromFunction.Get("a"));
        Assert.Equal(123, instanceFromFunction.Get("b"));

        var arrayInstance = (JsArray) _engine.Construct("Array", "abc", 123).AsObject();
        Assert.Equal((uint) 2, arrayInstance.Length);
        Assert.Equal("abc", arrayInstance[0]);
        Assert.Equal(123, arrayInstance[1]);
    }

    [Fact]
    public void FunctionInstancesCanBePassedToHost()
    {
        var engine = new Engine();
        Func<JsValue, JsValue[], JsValue> ev = null;

        void addListener(Func<JsValue, JsValue[], JsValue> callback)
        {
            ev = callback;
        }

        engine.SetValue("addListener", new Action<Func<JsValue, JsValue[], JsValue>>(addListener));

        engine.Execute(@"
                var a = 5;

                (function() {
                    var acc = 10;
                    addListener(function (val) {
                        a = (val || 0) + acc;
                    });
                })();
");

        Assert.Equal(5, engine.Evaluate("a"));

        ev(null, new JsValue[0]);
        Assert.Equal(10, engine.Evaluate("a"));

        ev(null, new JsValue[] { 20 });
        Assert.Equal(30, engine.Evaluate("a"));
    }

    [Fact]
    public void BoundFunctionsCanBePassedToHost()
    {
        var engine = new Engine();
        Func<JsValue, JsValue[], JsValue> ev = null;

        void addListener(Func<JsValue, JsValue[], JsValue> callback)
        {
            ev = callback;
        }

        engine.SetValue("addListener", new Action<Func<JsValue, JsValue[], JsValue>>(addListener));

        engine.Execute(@"
                var a = 5;

                (function() {
                    addListener(function (acc, val) {
                        a = (val || 0) + acc;
                    }.bind(null, 10));
                })();
            ");

        Assert.Equal(5, engine.Evaluate("a"));

        ev(null, new JsValue[0]);
        Assert.Equal(10, engine.Evaluate("a"));

        ev(null, new JsValue[] { 20 });
        Assert.Equal(30, engine.Evaluate("a"));
    }

    [Fact]
    public void ConstructorsCanBePassedToHost()
    {
        var engine = new Engine();
        Func<JsValue, JsValue[], JsValue> ev = null;

        void addListener(Func<JsValue, JsValue[], JsValue> callback)
        {
            ev = callback;
        }

        engine.SetValue("addListener", new Action<Func<JsValue, JsValue[], JsValue>>(addListener));

        engine.Execute(@"addListener(Boolean)");

        Assert.Equal(true, ev(JsValue.Undefined, new JsValue[] { "test" }));
        Assert.Equal(true, ev(JsValue.Undefined, new JsValue[] { 5 }));
        Assert.Equal(false, ev(JsValue.Undefined, new JsValue[] { false }));
        Assert.Equal(false, ev(JsValue.Undefined, new JsValue[] { 0}));
        Assert.Equal(false, ev(JsValue.Undefined, new JsValue[] { JsValue.Undefined }));
    }

    [Fact]
    public void FunctionsShouldResolveToSameReference()
    {
        _engine.SetValue("equal", new Action<object, object>(Assert.Equal));
        _engine.Execute(@"
                function testFn() {}
                equal(testFn, testFn);
            ");
    }

    [Fact]
    public void CanInvokeCallForFunctionInstance()
    {
        _engine.Evaluate(@"
                (function () {
                    function foo(a = 123) { return a; }
                    foo()
                })")
            .As<Function>().Call();

        var result = _engine.Evaluate(@"
                (function () {
                    class Foo { test() { return 123 } }
                    let f = new Foo()
                    return f.test()
                })")
            .As<Function>().Call();

        Assert.True(result.IsInteger());
        Assert.Equal(123, result.AsInteger());
    }

    [Fact]
    public void CanInvokeCallForFunctionInstanceWithDifferingArgCounts()
    {
        _engine.Execute("function foo() { return Array.from(arguments).join(','); }");
        var function = _engine.GetValue("foo");
        Assert.Equal("", function.Call());
        Assert.Equal("1", function.Call(1));
        Assert.Equal("1,2", function.Call(1, 2));
        Assert.Equal("1,2,3", function.Call(1, 2, 3));
        Assert.Equal("1,2,3,4", function.Call(1, 2, 3, 4));
    }

    [Fact]
    public void CanInvokeFunctionViaEngineInstance()
    {
        var function = _engine.Evaluate("function bar(a) { return a; }; bar;");

        Assert.Equal(123, _engine.Call(function, 123));
        Assert.Equal(123, _engine.Call("bar", 123));
    }

    [Fact]
    public void CanInvokeFunctionViaEngineInstanceWithCustomThisObj()
    {
        var function = _engine.Evaluate("function baz() { return this; }; baz;");

        Assert.Equal("I'm this!", TypeConverter.ToString(_engine.Call(function, "I'm this!", Arguments.Empty)));
        Assert.Equal("I'm this!", TypeConverter.ToString(function.Call("I'm this!", Arguments.Empty)));
    }

    [Fact]
    public void ArrowFunction()
    {
        const string Script = @"var f = (function() { return z => arguments[0]; }(5)); equal(5, f(6));";
        _engine.Execute(Script);
    }
}