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feat: 🎸 added TreeState
added TreeState, an immutable strucuture that represents the tree state
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‎index.d.ts

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@@ -135,4 +135,15 @@ interface Selectors {
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updateNode: (node: FlattenedNode, state: {[stateKey: string]: any}) => NodeAction;
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}
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interface State {
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flattenedTree: Array<number | string>[];
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tree: Node[];
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}
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export interface TreeState {
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getNodeAt: (state: State, index: number) => Node;
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getTree: (state: State) => Node[];
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createFromTree: (tree: Node[]) => State;
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}
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export const selectors: Selectors;

‎src/state/TreeState.js

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import {getFlattenedTreePaths} from '../selectors/getFlattenedTree';
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import {getNodeFromPath} from '../selectors/nodes';
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class State {
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flattenedTree = null;
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tree = null;
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constructor(tree, flattenedTree) {
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this.tree = tree;
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this.flattenedTree = flattenedTree || getFlattenedTreePaths(tree);
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}
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}
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export const validateState = state => {
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if (!(state instanceof State)) {
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throw new Error(`Expected a State instance but got ${typeof state}`);
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}
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};
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/**
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* Immutable structure that represents the TreeState.
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*/
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export default class TreeState {
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/**
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* Given a state, finds a node at a certain row index.
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* @param {State} state - The current state
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* @param {number} index - The visible row index
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* @return {State} An internal state representation
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*/
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static getNodeAt = (state, index) => {
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validateState(state);
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const rowPath = state.flattenedTree[index];
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if (!rowPath) {
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throw Error(
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`Tried to get node at row "${index}" but got nothing, the tree are ${state.flattenedTree.length} visible rows`,
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);
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}
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return getNodeFromPath(rowPath, state.tree);
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};
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/**
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* Given a state, gets the tree
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* @param {State} state - The current state
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* @return {Node[]} The tree
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*/
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static getTree = state => {
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validateState(state);
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return state.tree;
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};
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/**
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* Creates an instance of state.
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* @param {Node[]} tree - The original tree
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* @return {State} An internal state representation
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*/
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static createFromTree = tree => {
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if (!tree) {
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throw Error('A falsy tree was supplied in tree creation');
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}
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if (!Array.isArray(tree)) {
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throw Error('An invalid tree was supplied in creation');
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}
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return new State(tree);
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};
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}

‎src/state/__tests__/TreeState.test.js

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import TreeState from '../TreeState';
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import {Nodes} from '../../../testData/sampleTree';
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describe('TreeState', () => {
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describe('createFromTree', () => {
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test('should fail when falsy value is supplied', () => {
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expect(() => TreeState.createFromTree()).toThrowError('A falsy tree was supplied in tree creation');
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expect(() => TreeState.createFromTree('')).toThrowError('A falsy tree was supplied in tree creation');
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expect(() => TreeState.createFromTree(0)).toThrowError('A falsy tree was supplied in tree creation');
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expect(() => TreeState.createFromTree(false)).toThrowError('A falsy tree was supplied in tree creation');
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});
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test('should fail when an invalid value is supplied', () => {
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expect(() => TreeState.createFromTree({})).toThrowError('An invalid tree was supplied in creation');
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expect(() => TreeState.createFromTree('tree')).toThrowError('An invalid tree was supplied in creation');
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expect(() => TreeState.createFromTree(1234)).toThrowError('An invalid tree was supplied in creation');
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expect(() => TreeState.createFromTree(true)).toThrowError('An invalid tree was supplied in creation');
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});
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test('should create state when a valid tree is supplied', () => {
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const {tree, flattenedTree} = TreeState.createFromTree(Nodes);
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expect(tree).toEqual(Nodes);
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expect(flattenedTree).toMatchSnapshot();
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});
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});
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describe('getNodeAt', () => {
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test('should get a for an existing rowId', () => {
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expect(TreeState.getNodeAt(TreeState.createFromTree(Nodes), 0)).toBe(Nodes[0]);
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expect(TreeState.getNodeAt(TreeState.createFromTree(Nodes), 1)).toMatchSnapshot('2nd row');
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expect(TreeState.getNodeAt(TreeState.createFromTree(Nodes), 2)).toMatchSnapshot('3rd row');
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expect(TreeState.getNodeAt(TreeState.createFromTree(Nodes), 6)).toMatchSnapshot('7th row');
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});
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test('should fail with a custom error when supplied rowId does not exist', () => {
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expect(() => TreeState.getNodeAt(TreeState.createFromTree(Nodes), 25)).toThrowErrorMatchingSnapshot();
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});
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test('should fail for when invalid state is supplied', () => {
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expect(() => TreeState.getNodeAt('state', 0)).toThrowError('Expected a State instance but got string');
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expect(() => TreeState.getNodeAt(1225, 0)).toThrowError('Expected a State instance but got number');
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expect(() => TreeState.getNodeAt([], 0)).toThrowError('Expected a State instance but got object');
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expect(() => TreeState.getNodeAt({}, 0)).toThrowError('Expected a State instance but got object');
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expect(() => TreeState.getNodeAt(true, 0)).toThrowError('Expected a State instance but got boolean');
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expect(() => TreeState.getNodeAt(() => {}, 0)).toThrowError('Expected a State instance but got function');
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});
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});
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describe('getTree', () => {
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test('should get a tree', () => {
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expect(TreeState.getTree(TreeState.createFromTree(Nodes))).toEqual(Nodes);
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});
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test('should fail for when invalid state is supplied', () => {
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expect(() => TreeState.getTree('state')).toThrowError('Expected a State instance but got string');
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expect(() => TreeState.getTree(1225)).toThrowError('Expected a State instance but got number');
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expect(() => TreeState.getTree([])).toThrowError('Expected a State instance but got object');
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expect(() => TreeState.getTree({})).toThrowError('Expected a State instance but got object');
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expect(() => TreeState.getTree(true)).toThrowError('Expected a State instance but got boolean');
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expect(() => TreeState.getTree(() => {})).toThrowError('Expected a State instance but got function');
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});
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});
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});

‎src/state/__tests__/__snapshots__/TreeState.test.js.snap

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// Jest Snapshot v1, https://goo.gl/fbAQLP
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exports[`TreeState createFromTree should create state when a valid tree is supplied 1`] = `
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Array [
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Array [
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0,
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],
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Array [
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0,
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2,
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],
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Array [
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0,
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2,
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3,
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],
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Array [
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0,
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2,
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4,
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],
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Array [
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0,
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5,
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],
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Array [
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1,
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],
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Array [
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"z",
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],
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]
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`;
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exports[`TreeState getNodeAt should fail with a custom error when supplied rowId does not exist 1`] = `"Tried to get node at row \\"25\\" but got nothing, the tree are 7 visible rows"`;
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exports[`TreeState getNodeAt should get a for an existing rowId: 2nd row 1`] = `
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Object {
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"children": Array [
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Object {
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"id": 3,
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"name": "Leaf 3",
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"state": Object {
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"deletable": true,
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"favorite": true,
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},
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},
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Object {
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"id": 4,
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"name": "Leaf 4",
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},
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],
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"id": 2,
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"name": "Leaf 2",
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"state": Object {
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"deletable": true,
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"expanded": true,
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},
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}
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`;
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exports[`TreeState getNodeAt should get a for an existing rowId: 3rd row 1`] = `
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Object {
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"id": 3,
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"name": "Leaf 3",
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"state": Object {
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"deletable": true,
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"favorite": true,
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},
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}
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`;
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exports[`TreeState getNodeAt should get a for an existing rowId: 7th row 1`] = `
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Object {
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"id": "z",
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"name": "Leaf z",
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"state": Object {
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"deletable": true,
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"favorite": true,
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},
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}
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`;

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