如何正确使用javascript 来进行我们的程序开发

var foo = [1,2];
bar = foo;
bar[0] = 9;
console.log(foo[0],bar[0]); // => 9,9

//bad
var item = new Object();
//good
var item = {};

//bad
var superman = {
default: {clark: 'kent'},
private: true
};
//good
var superman = {
defaults: {clark: 'kent'},
hidden: true
};

//bad
var items = new Array();
//good
var items = [];

var someStack = [];
//bad
someStack[someStack.length] = 'vein';
//good
someStack.push('vein');

var len = items.length, //指的就是上面的内容...
itemCopy = [],
i;
//bad
for(i = 0; i < len ; ++i){
itemCopy[i] = items[i];
}
//good
itemCopy = items.slice(); //这里要注意了.这个我还真不知道...

//bad
var name = "Bob Parr";
//good
var name = 'Bob Parr';
//bad
var fullName = "Bob " + this.lastName;
//good
var fullName = 'Bob ' + this.lastName;

// bad
var errorMessage = 'This is a super long error that was thrown because of Batman. When you stop to think about how Batman had anything to do with this, you would get nowhere fast.';
// bad
var errorMessage = 'This is a super long error that was thrown because \
of Batman. When you stop to think about how Batman had anything to do \
with this, you would get nowhere \
fast.';
// good
var errorMessage = 'This is a super long error that was thrown because ' +
'of Batman. When you stop to think about how Batman had anything to do ' +
'with this, you would get nowhere fast.';

var items,
messages,
length,
i;
messages = [{
stat: 'success',
message: ' This one worked'
},{
stat: 'success',
message: ' This one worked'
},{
stat: 'success',
message: ' This one worked'
}
];
length = messages.length;
//bad
function inbox(messages){
items = '<ul>';
for (i = 0; i < length; i++) {
items += '<li>' + messages[i].message + '</li>';
}
return items + '</ul>';
}
//good
function inbox(messages){
items = [];
for( i = 0; i < length ; i++){
items[i] = messages[i].message;
}
return '<ul><li>' + items.join('</li><li>') + '</li></ul>';
}

//匿名函数表达式..
var anonymous = function(){
return true;
};
// 命名函数表达式.
var named = function named(){
return true;
};
//即时引用函数
(function(){
console.log('Welcome to the Internet. Please follow me.');
})();

//bad
if(currentUser){
function test(){
console.log('Nope.');
}
}
//good
var test;
if(currentUser){
test = function(){
console.log('Yup'); 
}; //be careful with the semi-colon.
}

var luke = {
jedi: true,
age: 28
};
//bad
var isJedi = luke['jedi'];
//good
var isJedi = luck.jedi;

var luke = {
jedi: true,
age: 28
};
function getProp(prop) {
return luke[prop];
}
var isJedi = getProp('jedi');