React库中的context和updater参数是什么? [英] What are context and updater arguments in the React library?
问题描述
我试图通过了解React React库,但无法理解 context
和 updater
是什么,它被传递到零件。
I was trying to understand the React through the React library, but couldn't understand what context
and updater
is, which is passed in to the Component.
以下是图书馆中的代码。
Following was the code in the library.
function Component(props, context, updater) {
this.props = props;
this.context = context;
this.refs = emptyObject;
// We initialize the default updater but the real one gets injected by the
// renderer.
this.updater = updater || ReactNoopUpdateQueue;
}
这些东西的目的是什么?
What is the purpose of these things?
推荐答案
背景
context
的目的是让开发者直接传递 props
到组件
,而不是通过的
子
/的道具
父母
(可能会非常复杂/混乱)。
Context
The purpose of context
is to enable devs to pass props
directly to components
, rather than via the props
of children
/ parents
(which can get very complicated / messy).
在某些情况下,您希望通过组件树传递数据,而无需在每个级别手动传递道具。您可以使用功能强大的上下文API直接在React中执行此操作。
In some cases, you want to pass data through the component tree without having to pass the props down manually at every level. You can do this directly in React with the powerful "context" API.
更新程序
updater
是一个对象
,其中包含方法
更新 DOM
。
Updater
updater
is an object
containing methods
to update the DOM
.
这在行<$中很明显c $ c> 61 和 79
。
// Line 61: Enqueue setState.
this.updater.enqueueSetState(this, partialState, callback, 'setState')
// Line 79: Force Update.
this.updater.enqueueForceUpdate(this, callback, 'forceUpdate')
这些<$使用 触发c $ c> methods
setState() 和 forceUpdate()
。
These methods
are triggered using setState()
and forceUpdate()
respectively.
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