class class1 {
    constructor() {
        var x2 = {
            doStuff: (callback) => () => {
                var _this = 2;
                return callback(this);
            }
        }
    }
}

class class2 {
    constructor() {
        var _this = 2;
        var x2 = {
            doStuff: (callback) => () => {
                return callback(this);
            }
        }
    }
}