UglifyJS/test/compress/dead-code.js

dead_code_1: {
    options = {
        dead_code: true
    };
    input: {
        function f() {
            a();
            b();
            x = 10;
            return;
            if (x) {
                y();
            }
        }
    }
    expect: {
        function f() {
            a();
            b();
            x = 10;
            return;
        }
    }
}

dead_code_2_should_warn: {
    options = {
        dead_code: true
    };
    input: {
        function f() {
            g();
            x = 10;
            throw "foo";
            // completely discarding the `if` would introduce some
            // bugs.  UglifyJS v1 doesn't deal with this issue; in v2
            // we copy any declarations to the upper scope.
            if (x) {
                y();
                var x;
                function g(){};
                // but nested declarations should not be kept.
                (function(){
                    var q;
                    function y(){};
                })();
            }
        }
    }
    expect: {
        function f() {
            g();
            x = 10;
            throw "foo";
            var x;
            function g(){};
        }
    }
}

dead_code_constant_boolean_should_warn_more: {
    options = {
        dead_code    : true,
        loops        : true,
        booleans     : true,
        conditionals : true,
        evaluate     : true,
        side_effects : true,
    };
    input: {
        while (!((foo && bar) || (x + "0"))) {
            console.log("unreachable");
            var foo;
            function bar() {}
        }
        for (var x = 10, y; x && (y || x) && (!typeof x); ++x) {
            asdf();
            foo();
            var moo;
        }
    }
    expect: {
        var foo;
        function bar() {}
        // nothing for the while
        // as for the for, it should keep:
        var x = 10, y;
        var moo;
    }
    expect_stdout: true
}

try_catch_finally: {
    options = {
        conditionals: true,
        dead_code: true,
        evaluate: true,
    }
    input: {
        var a = 1;
        !function() {
            try {
                if (false) throw x;
            } catch (a) {
                var a = 2;
                console.log("FAIL");
            } finally {
                a = 3;
                console.log("PASS");
            }
        }();
        try {
            console.log(a);
        } finally {
        }
    }
    expect: {
        var a = 1;
        !function() {
            var a;
            a = 3;
            console.log("PASS");
        }();
        try {
            console.log(a);
        } finally {
        }
    }
    expect_stdout: [
        "PASS",
        "1",
    ]
}

accessor: {
    options = {
        side_effects: true,
    }
    input: {
        ({
            get a() {},
            set a(v){
                this.b = 2;
            },
            b: 1
        });
    }
    expect: {}
}