diff --git a/docs/api/locations.md b/docs/api/locations.md
index 3325ef6d4..275374596 100644
--- a/docs/api/locations.md
+++ b/docs/api/locations.md
@@ -28,7 +28,7 @@ type Path = number[]
 interface Point {
     path: Path
     offset: number  
-    [key: string]: any
+    [key: string]: unknown
 }
 ```
 
@@ -68,7 +68,7 @@ Options: `{affinity?: 'forward' | 'backward' | null}`
 interface Range {
     anchor: Point
     focus: Point
-    [key: string]: any
+    [key: string]: unknown
 }
 ```
 
diff --git a/docs/api/nodes.md b/docs/api/nodes.md
index 6fea366d6..b18321f9b 100644
--- a/docs/api/nodes.md
+++ b/docs/api/nodes.md
@@ -123,7 +123,7 @@ interface Editor {
   selection: Range | null
   operations: Operation[]
   marks: Record<string, any> | null
-  [key: string]: any
+  [key: string]: unknown
 
   // Schema-specific node behaviors.
   isInline: (element: Element) => boolean
@@ -212,7 +212,7 @@ Apply an operation in the editor.
 ```typescript
 interface Element {
   children: Node[]
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
@@ -237,7 +237,7 @@ Check if an element matches a set of `props`. Note: This checks custom propertie
 ```typescript
 interface Text {
     text: string,
-    [key: string]: any
+    [key: string]: unknown
 }
 ```
 
diff --git a/docs/concepts/01-interfaces.md b/docs/concepts/01-interfaces.md
index e77443cfc..74f40a69b 100644
--- a/docs/concepts/01-interfaces.md
+++ b/docs/concepts/01-interfaces.md
@@ -5,7 +5,7 @@ Slate works with pure JSON objects. All it requires is that those JSON objects c
 ```ts
 interface Text {
   text: string
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
@@ -22,7 +22,7 @@ To take another example, the `Element` node interface in Slate is:
 ```ts
 interface Element {
   children: Node[]
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
diff --git a/docs/concepts/02-nodes.md b/docs/concepts/02-nodes.md
index a43f36ab9..6454bbd1a 100644
--- a/docs/concepts/02-nodes.md
+++ b/docs/concepts/02-nodes.md
@@ -55,7 +55,7 @@ Elements make up the middle layers of a richtext document. They are the nodes th
 ```ts
 interface Element {
   children: Node[]
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
@@ -126,7 +126,7 @@ Text nodes are the lowest-level nodes in the tree, containing the text content o
 ```ts
 interface Text {
   text: string
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
diff --git a/docs/concepts/03-locations.md b/docs/concepts/03-locations.md
index 795a121ed..f9b9f49fa 100644
--- a/docs/concepts/03-locations.md
+++ b/docs/concepts/03-locations.md
@@ -37,7 +37,7 @@ Points are slightly more specific than paths, and contain an `offset` into a spe
 interface Point {
   path: Path
   offset: number
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
@@ -71,7 +71,7 @@ Ranges are a way to refer not just to a single point in the document, but to a w
 interface Range {
   anchor: Point
   focus: Point
-  [key: string]: any
+  [key: string]: unknown
 }
 ```
 
diff --git a/docs/concepts/06-editor.md b/docs/concepts/06-editor.md
index 2657c2674..20e2e22bb 100644
--- a/docs/concepts/06-editor.md
+++ b/docs/concepts/06-editor.md
@@ -8,7 +8,7 @@ interface Editor {
   selection: Range | null
   operations: Operation[]
   marks: Record<string, any> | null
-  [key: string]: any
+  [key: string]: unknown
 
   // Schema-specific node behaviors.
   isInline: (element: Element) => boolean
diff --git a/packages/slate-react/src/components/editable.tsx b/packages/slate-react/src/components/editable.tsx
index 44fcc60ae..73b3452e4 100644
--- a/packages/slate-react/src/components/editable.tsx
+++ b/packages/slate-react/src/components/editable.tsx
@@ -708,7 +708,7 @@ export const Editable = (props: EditableProps) => {
               if (Hotkeys.isRedo(nativeEvent)) {
                 event.preventDefault()
 
-                if (editor.redo) {
+                if (typeof editor.redo === 'function') {
                   editor.redo()
                 }
 
@@ -718,7 +718,7 @@ export const Editable = (props: EditableProps) => {
               if (Hotkeys.isUndo(nativeEvent)) {
                 event.preventDefault()
 
-                if (editor.undo) {
+                if (typeof editor.undo === 'function') {
                   editor.undo()
                 }
 
diff --git a/packages/slate-react/src/components/leaf.tsx b/packages/slate-react/src/components/leaf.tsx
index 8ab9fcd25..0d3e438a4 100644
--- a/packages/slate-react/src/components/leaf.tsx
+++ b/packages/slate-react/src/components/leaf.tsx
@@ -43,7 +43,7 @@ const Leaf = (props: {
             opacity: '0.333',
           }}
         >
-          {leaf.placeholder}
+          {leaf.placeholder as React.ReactNode}
         </span>
         {children}
       </React.Fragment>
diff --git a/packages/slate-react/src/components/slate.tsx b/packages/slate-react/src/components/slate.tsx
index 49d5307b4..82b3caa0c 100644
--- a/packages/slate-react/src/components/slate.tsx
+++ b/packages/slate-react/src/components/slate.tsx
@@ -17,7 +17,7 @@ export const Slate = (props: {
   value: Node[]
   children: React.ReactNode
   onChange: (value: Node[]) => void
-  [key: string]: any
+  [key: string]: unknown
 }) => {
   const { editor, children, onChange, value, ...rest } = props
   const [key, setKey] = useState(0)
diff --git a/packages/slate/src/interfaces/editor.ts b/packages/slate/src/interfaces/editor.ts
index 782c36aed..5e48a5ff1 100755
--- a/packages/slate/src/interfaces/editor.ts
+++ b/packages/slate/src/interfaces/editor.ts
@@ -38,7 +38,7 @@ export interface Editor {
   selection: Range | null
   operations: Operation[]
   marks: Record<string, any> | null
-  [key: string]: any
+  [key: string]: unknown
 
   // Schema-specific node behaviors.
   isInline: (element: Element) => boolean
@@ -1332,7 +1332,7 @@ export const Editor = {
         // the operation was applied.
         parent.children.splice(index, 1)
         const truePath = Path.transform(path, op)!
-        const newParent = Node.get(editor, Path.parent(truePath))
+        const newParent = Node.get(editor, Path.parent(truePath)) as Ancestor
         const newIndex = truePath[truePath.length - 1]
 
         newParent.children.splice(newIndex, 0, node)
diff --git a/packages/slate/src/interfaces/element.ts b/packages/slate/src/interfaces/element.ts
index b63c9b428..34361e8c2 100755
--- a/packages/slate/src/interfaces/element.ts
+++ b/packages/slate/src/interfaces/element.ts
@@ -9,7 +9,7 @@ import { Editor, Node, Path } from '..'
 
 export interface Element {
   children: Node[]
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export const Element = {
diff --git a/packages/slate/src/interfaces/operation.ts b/packages/slate/src/interfaces/operation.ts
index e8791fcd4..c9cc22088 100755
--- a/packages/slate/src/interfaces/operation.ts
+++ b/packages/slate/src/interfaces/operation.ts
@@ -5,7 +5,7 @@ export type InsertNodeOperation = {
   type: 'insert_node'
   path: Path
   node: Node
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type InsertTextOperation = {
@@ -13,7 +13,7 @@ export type InsertTextOperation = {
   path: Path
   offset: number
   text: string
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type MergeNodeOperation = {
@@ -22,21 +22,21 @@ export type MergeNodeOperation = {
   position: number
   target: number | null
   properties: Partial<Node>
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type MoveNodeOperation = {
   type: 'move_node'
   path: Path
   newPath: Path
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type RemoveNodeOperation = {
   type: 'remove_node'
   path: Path
   node: Node
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type RemoveTextOperation = {
@@ -44,7 +44,7 @@ export type RemoveTextOperation = {
   path: Path
   offset: number
   text: string
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type SetNodeOperation = {
@@ -52,25 +52,25 @@ export type SetNodeOperation = {
   path: Path
   properties: Partial<Node>
   newProperties: Partial<Node>
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type SetSelectionOperation =
   | {
       type: 'set_selection'
-      [key: string]: any
+      [key: string]: unknown
       properties: null
       newProperties: Range
     }
   | {
       type: 'set_selection'
-      [key: string]: any
+      [key: string]: unknown
       properties: Partial<Range>
       newProperties: Partial<Range>
     }
   | {
       type: 'set_selection'
-      [key: string]: any
+      [key: string]: unknown
       properties: Range
       newProperties: null
     }
@@ -81,7 +81,7 @@ export type SplitNodeOperation = {
   position: number
   target: number | null
   properties: Partial<Node>
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export type NodeOperation =
diff --git a/packages/slate/src/interfaces/point.ts b/packages/slate/src/interfaces/point.ts
index 20fce6759..971b6486c 100755
--- a/packages/slate/src/interfaces/point.ts
+++ b/packages/slate/src/interfaces/point.ts
@@ -12,7 +12,7 @@ import { Operation, Path } from '..'
 export interface Point {
   path: Path
   offset: number
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export const Point = {
diff --git a/packages/slate/src/interfaces/range.ts b/packages/slate/src/interfaces/range.ts
index e2d60c681..5f53bfcd8 100755
--- a/packages/slate/src/interfaces/range.ts
+++ b/packages/slate/src/interfaces/range.ts
@@ -11,7 +11,7 @@ import { Operation, Path, Point, PointEntry } from '..'
 export interface Range {
   anchor: Point
   focus: Point
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export const Range = {
diff --git a/packages/slate/src/interfaces/text.ts b/packages/slate/src/interfaces/text.ts
index 80ca65f22..96eb750c4 100755
--- a/packages/slate/src/interfaces/text.ts
+++ b/packages/slate/src/interfaces/text.ts
@@ -9,7 +9,7 @@ import { Range } from '..'
 
 export interface Text {
   text: string
-  [key: string]: any
+  [key: string]: unknown
 }
 
 export const Text = {
diff --git a/packages/slate/src/transforms/general.ts b/packages/slate/src/transforms/general.ts
index cd6e7da00..5b170dfd4 100755
--- a/packages/slate/src/transforms/general.ts
+++ b/packages/slate/src/transforms/general.ts
@@ -10,7 +10,7 @@ import {
   Descendant,
   NodeEntry,
   Path,
-  Transforms,
+  Ancestor,
 } from '..'
 
 export const GeneralTransforms = {
@@ -104,7 +104,7 @@ export const GeneralTransforms = {
         // the operation was applied.
         parent.children.splice(index, 1)
         const truePath = Path.transform(path, op)!
-        const newParent = Node.get(editor, Path.parent(truePath))
+        const newParent = Node.get(editor, Path.parent(truePath)) as Ancestor
         const newIndex = truePath[truePath.length - 1]
 
         newParent.children.splice(newIndex, 0, node)
diff --git a/packages/slate/src/transforms/node.ts b/packages/slate/src/transforms/node.ts
index 03d1e4f3f..ec07de9c0 100644
--- a/packages/slate/src/transforms/node.ts
+++ b/packages/slate/src/transforms/node.ts
@@ -8,6 +8,8 @@ import {
   Range,
   Text,
   Transforms,
+  NodeEntry,
+  Ancestor,
 } from '..'
 
 export const NodeTransforms = {
@@ -168,7 +170,8 @@ export const NodeTransforms = {
           )
         }
 
-        const [parent, parentPath] = Editor.node(editor, Path.parent(path))
+        const parentNodeEntry = Editor.node(editor, Path.parent(path))
+        const [parent, parentPath] = parentNodeEntry as NodeEntry<Ancestor>
         const index = path[path.length - 1]
         const { length } = parent.children
 
@@ -721,7 +724,7 @@ export const NodeTransforms = {
 
       for (const pathRef of pathRefs) {
         const path = pathRef.unref()!
-        const [node] = Editor.node(editor, path)
+        const [node] = Editor.node(editor, path) as NodeEntry<Ancestor>
         let range = Editor.range(editor, path)
 
         if (split && rangeRef) {
@@ -823,7 +826,8 @@ export const NodeTransforms = {
             : Path.common(firstPath, lastPath)
 
           const range = Editor.range(editor, firstPath, lastPath)
-          const [commonNode] = Editor.node(editor, commonPath)
+          const commonNodeEntry = Editor.node(editor, commonPath)
+          const [commonNode] = commonNodeEntry as NodeEntry<Ancestor>
           const depth = commonPath.length + 1
           const wrapperPath = Path.next(lastPath.slice(0, depth))
           const wrapper = { ...element, children: [] }