JavaScript核心编程（代码片段）

var a = function () {
    function someSetup() {
        var setup = 'done';
    }
    function actualWork() {
        alert('Worky-worky');
        //return true;
    }
    someSetup();
    return actualWork;
}();

a(); // 打印出了 Worky-worky

function f() {
    var a = [];
    var i;
    
    for(i = 0; i < 3; i++) {
        a[i] = (function (x) {
            return function () {
                return x;
            }
        })(i);
    }
    
    return a;
}

var a = f();
console.log(a[0]()); // 0
console.log(a[1]()); // 1
console.log(a[2]()); // 2

var getValue, setValue;

(function () {
    var secret = 0;
    getValue = function () {
        return secret;
    };
    setValue = function (v) {
        secret = v;
    };
})();

console.log(getValue());
setValue(2);
console.log(getValue());

// 迭代器
function setup(x) {
    var i = 0;
    return function () {
        return x[i++];
    };
}

var next = setup(['a', 'b', 'c']);
console.log(next()); // a
console.log(next()); // b
console.log(next()); // c

// 构造函数
function Hero() {
    this.occupation = 'Ninja';
}

var hero = new Hero();
console.log(hero.occupation);

function Hero(name) {
    this.name = name;
    this.occupation = 'Painer';
    this.whoAreYou = function () {
        return "I'm " + this.name + " and I'm a " + this.occupation;
    };
}

var hero = new Hero('Nico');
document.writeln(hero.whoAreYou());

(function (count) {
    if(count < 5) {
        alert(count);
        arguments.callee(++count);
    }
})(1);

// 正则表达式
function replaceCallback(match) {
    return '_' + match.toLowerCase();
}

var s = 'HelloJavaScriptWorld';

console.log(s.replace(/[A-Z]/g, replaceCallback)); // _hello_java_script_world