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# \_.bindKey

**语法：**

```javascript
_.bindKey(object, key, [partials])
```

**源代码链接：**[source](https://github.com/lodash/lodash/blob/4.17.10/lodash.js#L10148)

**npm包链接：**[npm package](https://www.npmjs.com/package/lodash.bindkey)

**描述：**

创建一个函数,在`object[key]`上通过接收`partials`附加参数，调用这个方法。

这个方法与[`_.bind`](https://lodash.com/docs/4.17.10#bind)的不同之处在于允许重新定义绑定函数即使它还不存在。 浏览[Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)了解更多详情。

`_.bind.placeholder`值，默认是以`_`作为附加部分参数的占位符。

**开始版本：**0.10.0

**参数：**

* `object (Object)`: 需要绑定函数的对象。
* `key (string)`: 需要绑定函数对象的键。
* `[partials] (...*)`: 附加的部分参数。

**返回值：**

* `(Function)`: 返回新的绑定函数。

**例子：**

```javascript
var object = {
  'user': 'fred',
  'greet': function(greeting, punctuation) {
    return greeting + ' ' + this.user + punctuation;
  }
};

var bound = _.bindKey(object, 'greet', 'hi');
bound('!');
// => 'hi fred!'

object.greet = function(greeting, punctuation) {
  return greeting + 'ya ' + this.user + punctuation;
};

bound('!');
// => 'hiya fred!'

// Bound with placeholders.
var bound = _.bindKey(object, 'greet', _, '!');
bound('hi');
// => 'hiya fred!'
```