docs: add description of opennessState parameter of recomputeTree method

Author: Lodin

README.md

@@ -5,13 +5,9 @@
 [![Build Status](https://img.shields.io/travis/Lodin/react-vtree/master.svg)](https://travis-ci.org/Lodin/react-vtree)
 [![Test Coverage](https://img.shields.io/codecov/c/github/Lodin/react-vtree/master.svg)](https://codecov.io/gh/Lodin/react-vtree)
 
-This package provides a lightweight and flexible solution for rendering large
-tree structures. It is built on top of the [react-window](https://github.com/bvaughn/react-window)
-library.
+This package provides a lightweight and flexible solution for rendering large tree structures. It is built on top of the [react-window](https://github.com/bvaughn/react-window) library.
 
-**Attention!** This library is entirely rewritten to work with the `react-window`. If
-you are looking for the tree view solution for the [react-virtualized](https://github.com/bvaughn/react-virtualized),
-take a look at [react-virtualized-tree](https://github.com/diogofcunha/react-virtualized-tree).
+**Attention!** This library is entirely rewritten to work with the `react-window`. If you are looking for the tree view solution for the [react-virtualized](https://github.com/bvaughn/react-virtualized), take a look at [react-virtualized-tree](https://github.com/diogofcunha/react-virtualized-tree).
 
 ## Installation
 
@@ -129,73 +125,55 @@ const Example = () => (
 
 #### Props
 
-The component receives all the props of the `FixedSizeList` component except for
-the `itemCount`. Additional properties are the following:
+The component receives all the props of the `FixedSizeList` component except for the `itemCount`. Additional properties are the following:
 
 ##### `children`
 
-The `Node` component that is responsible for rendering each node. It receives
-all the properties [`Row`](https://react-window.now.sh/#/api/FixedSizeList)
-recieves except for the `index` prop plus the following properties:
+The `Node` component that is responsible for rendering each node. It receives all the properties [`Row`](https://react-window.now.sh/#/api/FixedSizeList) recieves except for the `index` prop plus the following properties:
 
 - `data: object` - a data object yielded by the `treeWalker` function.
 - `isOpen: boolean` - a current openness status of the node.
-- `toggle(): function` - a function to change the openness state of the node. It
-  receives no arguments and can be provided directly as an `onClick` handler.
-- `treeData: any` - any data provided via the `itemData` property of the
-  `FixedSizeTree` component.
+- `toggle(): function` - a function to change the openness state of the node. It receives no arguments and can be provided directly as an `onClick` handler.
+- `treeData: any` - any data provided via the `itemData` property of the `FixedSizeTree` component.
 
 ##### `rowComponent: component`
 
-This property receives a custom `Row` component for the `FixedSizeList` that
-will override the default one. It can be used for adding new functionality to an
-existing one by wrapping the default `Row` into a custom component.
+This property receives a custom `Row` component for the `FixedSizeList` that will override the default one. It can be used for adding new functionality to an existing one by wrapping the default `Row` into a custom component.
 
 ##### `* treeWalker(refresh: boolean)`
 
-An iterator function that walks around the tree and yields each node one by one
-flattening them to an array that can be easily displayed by `FixedSizeList`
-component.
+An iterator function that walks around the tree and yields each node one by one flattening them to an array that can be easily displayed by `FixedSizeList` component.
 
-The function receives `refresh` parameter. If it is `true`, the component
-requests the full node update and expects the complete data object yielded. If
-it is `false`, the component awaits only the node id to update the order of
-displayed nodes.
+The function receives `refresh` parameter. If it is `true`, the component requests the full node update and expects the complete data object yielded. If it is `false`, the component awaits only the node id to update the order of displayed nodes.
 
 The data object should contain the following required properties:
 
 - `id` - a unique identifier of the node.
 - `isOpenByDefault` - a default openness state of the node.
 
-You can add any other property you need. This object will be sent directly to
-the `Node` component.
+You can add any other property you need. This object will be sent directly to the `Node` component.
 
-Yielding the object gets the current openness state of the node. Basing on it,
-you should decide if the node's children are going to be rendered.
+Yielding the object gets the current openness state of the node. Basing on it, you should decide if the node's children are going to be rendered.
 
 #### Methods
 
-The component provides all the methods `FixedSizeList` provides with the
-following changes:
+The component provides all the methods `FixedSizeList` provides with the following changes:
 
 ##### `scrollToItem(id: string | symbol, align?: Align): void`
 
 The `scrollToItem` method receives node `id` instead of `index`.
 
 ##### `async recomputeTree(options): void`
 
-This method runs the `treeWalker` function again and, basing on the received
-options, updates either nodes or their order.
+This method runs the `treeWalker` function again and, basing on the received options, updates either nodes or their order.
 
 It receives options object with the following parameters:
 
-- `refreshNodes: boolean` - if this parameter is `true`, `treeWalker` will
-  receive `refresh` option, and the component will expect the data object yielded.
-  If this parameter is either `false` or not provided, the component will expect
-  string id.
-- `useDefaultOpenness: boolean` - if this parameter is `true`, openness state of
-  all nodes will be reset to `isOpenByDefault`. Nodes updated during the tree
-  walking will use the new `isOpenByDefault` value.
+- `opennessState: Record<string, boolean>` - nodes whose IDs are specified as keys of this object will be opened or closed according to boolean values. If the value is `true`, node will be opened; otherwise, it will be closed. This object can be used for changing nodes' openness programmatically without re-creating the `treeWalker` generator.
+  
+  **NOTE**: If you specify both `useDefaultOpenness` and `opennessState`, `opennessState` will be overridden by `useDefaultOpenness` results.
+- `refreshNodes: boolean` - if this parameter is `true`, `treeWalker` will receive `refresh` option, and the component will expect the data object yielded. If this parameter is either `false` or not provided, the component will expect string id.
+- `useDefaultOpenness: boolean` - if this parameter is `true`, openness state of all nodes will be reset to `isOpenByDefault`. Nodes updated during the tree walking will use the new `isOpenByDefault` value.
 
 ### `VariableSizeTree`
 
@@ -292,57 +270,41 @@ const Example = () => (
 
 #### Props
 
-The component receives all the props of the `VariableSizeList` component except
-for the `itemCount` and `itemSize`. `itemSize` is still available but not
-required, and should be used only if the default behavior is not enough.
-Additional properties are the following:
+The component receives all the props of the `VariableSizeList` component except for the `itemCount` and `itemSize`. `itemSize` is still available but not required, and should be used only if the default behavior is not enough. Additional properties are the following:
 
 ##### `children`
 
-The `Node` component. It is the same as the [`FixedSizeTree`](#fixedsizetree)'s
-one but receives two additional properties:
+The `Node` component. It is the same as the [`FixedSizeTree`](#fixedsizetree)'s one but receives two additional properties:
 
 - `height: number` - a current height of the node.
-- `resize(newHeight: number, shouldForceUpdate?: boolean): function` - a
-  function to change the height of the node. It receives two parameters:
+- `resize(newHeight: number, shouldForceUpdate?: boolean): function` - a function to change the height of the node. It receives two parameters:
   - `newHeight: number` - a new height of the node.
-  - `shouldForceUpdate: boolean` - an optional argument that will be sent to the
-    [`resetAfterIndex`](https://react-window.now.sh/#/api/VariableSizeList)
-    method.
+  - `shouldForceUpdate: boolean` - an optional argument that will be sent to the [`resetAfterIndex`](https://react-window.now.sh/#/api/VariableSizeList) method.
 
 ##### `rowComponent: component`
 
-This property receives a custom `Row` component for the `VariableSizeList` that
-will override the default one. It can be used for adding new functionality to an
-existing one by wrapping the default `Row` into a custom component.
+This property receives a custom `Row` component for the `VariableSizeList` that will override the default one. It can be used for adding new functionality to an existing one by wrapping the default `Row` into a custom component.
 
 ##### `* treeWalker(refresh: boolean)`
 
-An iterator function that walks over the tree. It behaves the same as
-`FixedSizeTree`'s `treeWalker`, but there one additional required property for
-the data object:
+An iterator function that walks over the tree. It behaves the same as `FixedSizeTree`'s `treeWalker`, but there one additional required property for the data object:
 
 - `defaultHeight: number` - the default height of the node.
 
 #### Methods
 
-The component provides all the methods `VariableSizeList` provides with the
-following changes:
+The component provides all the methods `VariableSizeList` provides with the following changes:
 
 ##### `scrollToItem(id: string | symbol, align?: Align): void`
 
 The `scrollToItem` method receives node `id` instead of `index`.
 
 ##### `resetAfterId(id: string | symbol, shouldForceUpdate: boolean = false): void`
 
-This method replaces the `resetAfterIndex` method of `VariableSizeList`, but
-works exactly the same. It receives node `id` as a first argument.
+This method replaces the `resetAfterIndex` method of `VariableSizeList`, but works exactly the same. It receives node `id` as a first argument.
 
 ##### `async recomputeTree(options): void`
 
-This method works exactly the same as the `FixedSizeTree`'s one, but receives
-one additional option:
+This method works exactly the same as the `FixedSizeTree`'s one, but receives one additional option:
 
-- `useDefaultHeight: boolean` - if this parameter is `true`, the height of
-  all nodes will be reset to `defaultHeight`. Nodes updated during the tree
-  walking will use the new `defaultHeight` value.
+- `useDefaultHeight: boolean` - if this parameter is `true`, the height of all nodes will be reset to `defaultHeight`. Nodes updated during the tree walking will use the new `defaultHeight` value.