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Fix coding style in docs/proxy.md

This commit is contained in:
Xcat Liu 2016-05-18 13:43:26 +08:00
parent 307932e155
commit 24bcfb52ed

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@ -35,7 +35,7 @@ obj.count = 1
ES6原生提供Proxy构造函数用来生成Proxy实例。
```javascript
var proxy = new Proxy(target, handler)
var proxy = new Proxy(target, handler);
```
Proxy对象的所有用法都是上面这种形式不同的只是`handler`参数的写法。其中,`new Proxy()`表示生成一个Proxy实例target参数表示所要拦截的目标对象`handler`参数也是一个对象,用来定制拦截行为。
@ -73,7 +73,7 @@ target.a // "b"
一个技巧是将Proxy对象设置到`object.proxy`属性,从而可以在`object`对象上调用。
```javascript
var object = { proxy: new Proxy(target, handler) }
var object = { proxy: new Proxy(target, handler) };
```
Proxy实例也可以作为其他对象的原型对象。
@ -97,15 +97,15 @@ obj.time // 35
var handler = {
get: function(target, name) {
if (name === 'prototype') return Object.prototype;
return 'Hello, '+ name;
return 'Hello, ' + name;
},
apply: function(target, thisBinding, args) { return args[0]; },
construct: function(target, args) { return args[1]; }
};
var fproxy = new Proxy(function(x,y) {
return x+y;
}, handler);
var fproxy = new Proxy(function(x, y) {
return x + y;
}, handler);
fproxy(1,2); // 1
new fproxy(1,2); // 2
@ -357,7 +357,7 @@ var handler = {
invariant(key, 'set');
return true;
}
}
};
function invariant (key, action) {
if (key[0] === '_') {
throw new Error(`Invalid attempt to ${action} private "${key}" property`);
@ -382,7 +382,7 @@ var handler = {
apply (target, ctx, args) {
return Reflect.apply(...arguments);
}
}
};
```
`apply`方法可以接受三个参数,分别是目标对象、目标对象的上下文对象(`this`)和目标对象的参数数组。
@ -461,7 +461,7 @@ var p = new Proxy(obj, {
}
});
"a" in p; // TypeError is thrown
"a" in p // TypeError is thrown
```
上面代码中,`obj`对象禁止扩展,结果使用`has`拦截就会报错。
@ -475,7 +475,7 @@ var handler = {
construct (target, args) {
return new target(...args);
}
}
};
```
下面是一个例子。
@ -515,15 +515,15 @@ var handler = {
invariant(key, 'delete');
return true;
}
}
};
function invariant (key, action) {
if (key[0] === '_') {
throw new Error(`Invalid attempt to ${action} private "${key}" property`);
}
}
var target = { _prop: 'foo' }
var proxy = new Proxy(target, handler)
var target = { _prop: 'foo' };
var proxy = new Proxy(target, handler);
delete proxy._prop
// Error: Invalid attempt to delete private "_prop" property
```
@ -537,11 +537,11 @@ delete proxy._prop
```javascript
var handler = {
defineProperty (target, key, descriptor) {
return false
return false;
}
}
var target = {}
var proxy = new Proxy(target, handler)
};
var target = {};
var proxy = new Proxy(target, handler);
proxy.foo = 'bar'
// TypeError: proxy defineProperty handler returned false for property '"foo"'
```
@ -557,9 +557,9 @@ var handler = {
enumerate (target) {
return Object.keys(target).filter(key => key[0] !== '_')[Symbol.iterator]();
}
}
var target = { prop: 'foo', _bar: 'baz', _prop: 'foo' }
var proxy = new Proxy(target, handler)
};
var target = { prop: 'foo', _bar: 'baz', _prop: 'foo' };
var proxy = new Proxy(target, handler);
for (let key in proxy) {
console.log(key);
// "prop"
@ -607,11 +607,11 @@ for (var x in p) {} // 报错
var handler = {
getOwnPropertyDescriptor (target, key) {
if (key[0] === '_') {
return
return;
}
return Object.getOwnPropertyDescriptor(target, key)
return Object.getOwnPropertyDescriptor(target, key);
}
}
};
var target = { _foo: 'bar', baz: 'tar' };
var proxy = new Proxy(target, handler);
Object.getOwnPropertyDescriptor(proxy, 'wat')
@ -682,7 +682,7 @@ var p = new Proxy({}, {
}
});
Object.isExtensible(p); // 报错
Object.isExtensible(p) // 报错
```
### ownKeys()
@ -732,7 +732,7 @@ for (let key of Object.keys(proxy)) {
`preventExtensions`方法拦截`Object.preventExtensions()`。该方法必须返回一个布尔值。
这个方法有一个限制,只有当`Object.isExtensible(proxy)``false`(即不可扩展)时,`proxy.preventExtensions`才能返回true否则会报错。
这个方法有一个限制,只有当`Object.isExtensible(proxy)``false`(即不可扩展)时,`proxy.preventExtensions`才能返回`true`,否则会报错。
```javascript
var p = new Proxy({}, {
@ -741,7 +741,7 @@ var p = new Proxy({}, {
}
});
Object.preventExtensions(p); // 报错
Object.preventExtensions(p) // 报错
```
上面代码中,`proxy.preventExtensions`方法返回`true`,但这时`Object.isExtensible(proxy)`会返回`true`,因此报错。
@ -773,7 +773,7 @@ var handler = {
setPrototypeOf (target, proto) {
throw new Error('Changing the prototype is forbidden');
}
}
};
var proto = {};
var target = function () {};
var proxy = new Proxy(target, handler);
@ -915,7 +915,7 @@ Reflect.apply(Math.floor, undefined, [1.75]) // 1
var obj = {
get foo() { return this.bar(); },
bar: function() { ... }
}
};
// 下面语句会让 this.bar()
// 变成调用 wrapper.bar()