能够对于文字、段落乃至任何元素的精准定位 并做出增删改查，都是在开发一款富文本编辑器时一项最基本也是最重要的功能之一。让我们先来看看Slate中对于如何在文档树中定位元素是怎么定义的[源码]：
/**
- The
Locationinterface is a union of the ways to refer to a specific - location in a Slate document: paths, points or ranges.
- Methods will often accept a
Locationinstead of requiring only aPath, PointorRange. This eliminates the need for developers to manage- converting between the different interfaces in their own code base.
*/
export type Location = Path | Point | Range
Location是一个包含了Path、Point及Range的联合类型，代指了Slate中所有关于“定位”的概念，同时也方便了开发。例如在几乎所有的Transforms方法中，都可以通过传递Location参数来决定Transforms方法需要应用到文档中的哪些位置上[链接]。
All transforms support a parameter options. This includes options specific to the transform, and general NodeOptions to specify which Nodes in the document that the transform is applied to.
interface NodeOptions {
at?: Location
match?: (node: Node, path: Location) => boolean
mode?: 'highest' | 'lowest'
voids?: boolean
}
Path
Path是三个中最基本的概念，也是唯一一个不可拓展的类型。
/**
Patharrays are a list of indexes that describe a node's exact position in- a Slate node tree. Although they are usually relative to the root
Editor - object, they can be relative to any
Nodeobject.
*/
export type Path = number[]
Path类型就是一个数组，用来表示Slate文档树中自根节点root到指定node的绝对路径。我们以下边的示例来演示下各个node所代表的路径：
const initialValue: Descendant[] = [
// path: [0]
{
type: 'paragraph',
children: [
{ text: 'This is editable ' }, // path: [0, 0]
{ text: 'rich text!', bold: true } // path: [0, 1]
]
},
// path: [1]
{
type: 'paragraph',
children: [
{ text: 'It' so cool.' } // path: [1, 0]
]
}
]
虽然Path所代表的路径通常是以顶层Editor作为root节点的，但也会有其他情况，比如由Node提供的get方法中传入的Path参数则代表的是相对路径[源码]：
/**
- Get the descendant node referred to by a specific path. If th