LayoutTests/js/script-tests/class-syntax-name.js

description('Tests for ES6 class name semantics in class statements and expressions');

function shouldThrow(s, message) {
    var threw = false;
    try {
        eval(s);
    } catch(e) {
        threw = true;
        if (!message || e.toString() === eval(message))
            testPassed(s + ":::" + e.toString());
        else
            testFailed(s);
    }
    if (!threw)
        testFailed(s);
}

function shouldNotThrow(s) {
    var threw = false;
    try {
        eval(s);
    } catch(e) {
        threw = true;
    }
    if (threw)
        testFailed(s);
    else
        testPassed(s);
}

function shouldBe(a, b) {
    if (eval(a) === eval(b))
        testPassed(a + ":::" + b);
    else
        testFailed(a + ":::" + b);
}

function shouldBeTrue(s) {
    if (eval(s) === true)
        testPassed(s);
    else 
        testFailed(s);
}

function runTestShouldBe(statement, result) {
    shouldBe(statement, result);
    shouldBe("'use strict'; " + statement, result);
}

function runTestShouldBeTrue(statement) {
    shouldBeTrue(statement);
    shouldBeTrue("'use strict'; " + statement);
}

function runTestShouldThrow(statement) {
    shouldThrow(statement);
    shouldThrow("'use strict'; " + statement);
}

function runTestShouldNotThrow(statement) {
    shouldNotThrow(statement);
    shouldNotThrow("'use strict'; " + statement);
}

// Class statement. Class name added to global scope. Class name is available inside class scope and in global scope.
debug('Class statement');
runTestShouldThrow("A");
runTestShouldThrow("class {}");
runTestShouldThrow("class { constructor() {} }");
runTestShouldNotThrow("class A { constructor() {} }");
runTestShouldBe("class A { constructor() {} }; A.toString()", "'class A { constructor() {} }'");
runTestShouldBeTrue("class A { constructor() {} }; (new A) instanceof A");
runTestShouldBe("class A { constructor() { this.base = A; } }; (new A).base.toString()", "'class A { constructor() { this.base = A; } }'");
runTestShouldNotThrow("class A { constructor() {} }; class B extends A {};");
runTestShouldBe("class A { constructor() {} }; class B extends A { constructor() {} }; B.toString()", "'class B extends A { constructor() {} }'");
runTestShouldBeTrue("class A { constructor() {} }; class B extends A {}; (new B) instanceof A");
runTestShouldBeTrue("class A { constructor() {} }; class B extends A {}; (new B) instanceof B");
runTestShouldBe("class A { constructor() {} }; class B extends A { constructor() { super(); this.base = A; this.derived = B; } }; (new B).base.toString()", "'class A { constructor() {} }'");
runTestShouldBe("class A { constructor() {} }; class B extends A { constructor() { super(); this.base = A; this.derived = B; } }; (new B).derived.toString()", "'class B extends A { constructor() { super(); this.base = A; this.derived = B; } }'");

// Class expression. Class name not added to scope. Class name is available inside class scope.
debug(''); debug('Class expression');
runTestShouldThrow("A");
runTestShouldNotThrow("(class {})");
runTestShouldNotThrow("(class { constructor(){} })");
runTestShouldBe("typeof (class {})", '"function"');
runTestShouldNotThrow("(class A {})");
runTestShouldBe("typeof (class A {})", '"function"');
runTestShouldThrow("(class A {}); A");
runTestShouldNotThrow("new (class A {})");
runTestShouldBe("typeof (new (class A {}))", '"object"');
runTestShouldNotThrow("(new (class A { constructor() { this.base = A; } })).base");
runTestShouldBe("(new (class A { constructor() { this.base = A; } })).base.toString()", '"class A { constructor() { this.base = A; } }"');
runTestShouldNotThrow("class A {}; (class B extends A {})");
runTestShouldThrow("class A {}; (class B extends A {}); B");
runTestShouldNotThrow("class A {}; new (class B extends A {})");
runTestShouldNotThrow("class A {}; new (class B extends A { constructor() { super(); this.base = A; this.derived = B; } })");
runTestShouldBeTrue("class A {}; (new (class B extends A { constructor() { super(); this.base = A; this.derived = B; } })) instanceof A");
runTestShouldBe("class A { constructor() {} }; (new (class B extends A { constructor() { super(); this.base = A; this.derived = B; } })).base.toString()", "'class A { constructor() {} }'");
runTestShouldBe("class A { constructor() {} }; (new (class B extends A { constructor() { super(); this.base = A; this.derived = B; } })).derived.toString()", "'class B extends A { constructor() { super(); this.base = A; this.derived = B; } }'");

// Assignment of a class expression to a variable. Variable name available in scope, class name is not. Class name is available inside class scope.
debug(''); debug('Class expression assignment to variable');
runTestShouldThrow("A");
runTestShouldNotThrow("var VarA = class {}");
runTestShouldBe("var VarA = class { constructor() {} }; VarA.toString()", "'class { constructor() {} }'");
runTestShouldThrow("VarA");
runTestShouldNotThrow("var VarA = class A { constructor() {} }");
runTestShouldBe("var VarA = class A { constructor() {} }; VarA.toString()", "'class A { constructor() {} }'");
runTestShouldThrow("var VarA = class A { constructor() {} }; A.toString()");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; (new VarA) instanceof VarA");
runTestShouldBe("var VarA = class A { constructor() { this.base = A; } }; (new VarA).base.toString()", "'class A { constructor() { this.base = A; } }'");
runTestShouldNotThrow("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() {} };");
runTestShouldThrow("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() {} }; B");
runTestShouldBe("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() {} }; VarB.toString()", "'class B extends VarA { constructor() {} }'");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { }; (new VarB) instanceof VarA");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { }; (new VarB) instanceof VarB");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() { super(); this.base = VarA; this.derived = B; this.derivedVar = VarB; } }; (new VarB).base === VarA");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() { super(); this.base = VarA; this.derived = B; this.derivedVar = VarB; } }; (new VarB).derived === VarB");
runTestShouldBeTrue("var VarA = class A { constructor() {} }; var VarB = class B extends VarA { constructor() { super(); this.base = VarA; this.derived = B; this.derivedVar = VarB; } }; (new VarB).derivedVar === VarB");

// Class statement binding should be like `let`.
debug(''); debug('Class statement binding in other circumstances');
runTestShouldThrow("var result = A; result");
runTestShouldThrow("var result = A; class A {}; result");
runTestShouldThrow("class A { constructor() { A = 1; } }; new A");
runTestShouldBe("class A { constructor() { } }; A = 1; A", "1");
runTestShouldNotThrow("class A {}; var result = A; result");
shouldBe("eval('var Foo = 10'); Foo", "10");
shouldThrow("'use strict'; eval('var Foo = 10'); Foo");
shouldBe("eval('class Bar { constructor() {} }; Bar.toString()');", "'class Bar { constructor() {} }'");
shouldThrow("'use strict'; eval('class Bar { constructor() {} }'); Bar.toString()");