Backend API
        
    import React, { useState } from 'react';
import Gantt, {
  Tasks, Dependencies, Column, Validation, Editing,
} from 'devextreme-react/gantt';
import CheckBox, { ICheckBoxOptions } from 'devextreme-react/check-box';
import { tasks, dependencies } from './data.ts';
function App() {
  const [ganttConfig, setGanttConfig] = useState({
    autoUpdateParentTasks: true,
    validateDependencies: true,
    enablePredecessorGap: true,
  });
  const onEnablePredecessorGapChanged: ICheckBoxOptions['onValueChanged'] = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      enablePredecessorGap: value,
    });
  };
  const onAutoUpdateParentTasksChanged: ICheckBoxOptions['onValueChanged'] = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      autoUpdateParentTasks: value,
    });
  };
  const onValidateDependenciesChanged: ICheckBoxOptions['onValueChanged'] = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      validateDependencies: value,
    });
  };
  return (
    <div id="form-demo">
      <div className="options">
        <div className="caption">Options</div>
        <div className="option">
          <CheckBox
            text="Auto Update Parent Tasks"
            value={ganttConfig.autoUpdateParentTasks}
            onValueChanged={onAutoUpdateParentTasksChanged}
          />
        </div>
        {' '}
        <div className="option">
          <CheckBox
            text="Enable Dependency Validation"
            value={ganttConfig.validateDependencies}
            onValueChanged={onValidateDependenciesChanged}
          />
        </div>
        {' '}
        <div className="option">
          <CheckBox
            text="Enable Predecessor Gap"
            value={ganttConfig.enablePredecessorGap}
            onValueChanged={onEnablePredecessorGapChanged}
          />
        </div>
      </div>
      <div className="widget-container">
        <Gantt
          taskListWidth={500}
          height={700}
          taskTitlePosition="none">
          <Validation
            autoUpdateParentTasks={ganttConfig.autoUpdateParentTasks}
            validateDependencies={ganttConfig.validateDependencies}
            enablePredecessorGap={ganttConfig.enablePredecessorGap} />
          <Tasks dataSource={tasks} />
          <Dependencies dataSource={dependencies} />
          <Column dataField="title" caption="Task" width={300} />
          <Column dataField="start" caption="Start Date" />
          <Column dataField="end" caption="End Date" />
          <Editing enabled />
        </Gantt>
      </div>
    </div>
  );
}
export default App;
    
    import React, { useState } from 'react';
import Gantt, {
  Tasks, Dependencies, Column, Validation, Editing,
} from 'devextreme-react/gantt';
import CheckBox from 'devextreme-react/check-box';
import { tasks, dependencies } from './data.js';
function App() {
  const [ganttConfig, setGanttConfig] = useState({
    autoUpdateParentTasks: true,
    validateDependencies: true,
    enablePredecessorGap: true,
  });
  const onEnablePredecessorGapChanged = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      enablePredecessorGap: value,
    });
  };
  const onAutoUpdateParentTasksChanged = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      autoUpdateParentTasks: value,
    });
  };
  const onValidateDependenciesChanged = ({ value }) => {
    setGanttConfig({
      ...ganttConfig,
      validateDependencies: value,
    });
  };
  return (
    <div id="form-demo">
      <div className="options">
        <div className="caption">Options</div>
        <div className="option">
          <CheckBox
            text="Auto Update Parent Tasks"
            value={ganttConfig.autoUpdateParentTasks}
            onValueChanged={onAutoUpdateParentTasksChanged}
          />
        </div>{' '}
        <div className="option">
          <CheckBox
            text="Enable Dependency Validation"
            value={ganttConfig.validateDependencies}
            onValueChanged={onValidateDependenciesChanged}
          />
        </div>{' '}
        <div className="option">
          <CheckBox
            text="Enable Predecessor Gap"
            value={ganttConfig.enablePredecessorGap}
            onValueChanged={onEnablePredecessorGapChanged}
          />
        </div>
      </div>
      <div className="widget-container">
        <Gantt
          taskListWidth={500}
          height={700}
          taskTitlePosition="none"
        >
          <Validation
            autoUpdateParentTasks={ganttConfig.autoUpdateParentTasks}
            validateDependencies={ganttConfig.validateDependencies}
            enablePredecessorGap={ganttConfig.enablePredecessorGap}
          />
          <Tasks dataSource={tasks} />
          <Dependencies dataSource={dependencies} />
          <Column
            dataField="title"
            caption="Task"
            width={300}
          />
          <Column
            dataField="start"
            caption="Start Date"
          />
          <Column
            dataField="end"
            caption="End Date"
          />
          <Editing enabled />
        </Gantt>
      </div>
    </div>
  );
}
export default App;
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(
  <App />,
  document.getElementById('app'),
);
    
    export const currentDate = new Date(Date.now());
const month = currentDate.getMonth();
const year = currentDate.getFullYear();
export const tasks = [{
  id: 1,
  parentId: 0,
  title: 'Johnson Residence Construction Project',
  start: new Date(year, month - 1, 1),
  end: new Date(year, month - 1, 1),
  progress: 0,
}, {
  id: 2,
  parentId: 1,
  title: 'Planning and Pre-Construction Phase',
  start: new Date(year, month - 1, 1),
  end: new Date(year, month - 1, 1),
  progress: 0,
}, {
  id: 3,
  parentId: 2,
  title: 'Architectural Design and Site Planning',
  start: new Date(year, month - 1, 1),
  end: new Date(year, month - 1, 15),
  progress: 0,
}, {
  id: 4,
  parentId: 2,
  title: 'Engineering and Final Blueprint',
  start: new Date(year, month - 1, 8),
  end: new Date(year, month - 1, 15),
  progress: 0,
}, {
  id: 5,
  parentId: 2,
  title: 'City Permits and Contracts',
  start: new Date(year, month - 1, 15),
  end: new Date(year, month - 1, 18),
  progress: 0,
}, {
  id: 6,
  parentId: 1,
  title: 'Construction Phase',
  start: new Date(year, month - 1, 18),
  end: new Date(year, month - 1, 18),
  progress: 0,
}, {
  id: 7,
  parentId: 6,
  title: 'Grading and Excavation',
  start: new Date(year, month - 1, 18),
  end: new Date(year, month - 1, 22),
  progress: 0,
}, {
  id: 8,
  parentId: 6,
  title: 'Demolition and Removal',
  start: new Date(year, month - 1, 19),
  end: new Date(year, month - 1, 23),
  progress: 0,
}, {
  id: 9,
  parentId: 6,
  title: 'Foundation and Concrete ',
  start: new Date(year, month - 1, 22),
  end: new Date(year, month - 1, 28),
  progress: 0,
}, {
  id: 10,
  parentId: 6,
  title: 'Rough Framing and Carpentery',
  start: new Date(year, month - 1, 25),
  end: new Date(year, month, 5),
  progress: 0,
}, {
  id: 11,
  parentId: 6,
  title: 'Inspection (Structure)',
  start: new Date(year, month, 5),
  end: new Date(year, month, 5),
  progress: 0,
}, {
  id: 12,
  parentId: 6,
  title: 'Electrical Rough-in',
  start: new Date(year, month, 6),
  end: new Date(year, month, 19),
  progress: 0,
}, {
  id: 13,
  parentId: 6,
  title: 'Plumbing Rough-in',
  start: new Date(year, month, 19),
  end: new Date(year, month, 19),
  progress: 0,
}, {
  id: 14,
  parentId: 6,
  title: 'Heating and A/C',
  start: new Date(year, month, 19),
  end: new Date(year, month, 26),
  progress: 0,
}, {
  id: 15,
  parentId: 6,
  title: 'Drywall',
  start: new Date(year, month, 25),
  end: new Date(year, month + 1, 10),
  progress: 0,
}, {
  id: 16,
  parentId: 6,
  title: 'Painting (Exterior)',
  start: new Date(year, month + 1, 7),
  end: new Date(year, month + 1, 21),
  progress: 0,
}, {
  id: 17,
  parentId: 6,
  title: 'Interior Carpentery (Interior)',
  start: new Date(year, month + 1, 17),
  end: new Date(year, month + 1, 28),
  progress: 0,
}, {
  id: 18,
  parentId: 6,
  title: 'Flooring and Interior Paint',
  start: new Date(year, month + 1, 26),
  end: new Date(year, month + 2, 9),
  progress: 0,
}, {
  id: 19,
  parentId: 1,
  title: 'Final Phase',
  start: new Date(year, month + 2, 9),
  end: new Date(year, month + 2, 9),
  progress: 0,
}, {
  id: 20,
  parentId: 19,
  title: 'Review-Punch List',
  start: new Date(year, month + 2, 9),
  end: new Date(year, month + 2, 23),
  progress: 0,
}, {
  id: 21,
  parentId: 19,
  title: 'Final Inspection',
  start: new Date(year, month + 2, 24),
  end: new Date(year, month + 2, 24),
  progress: 0,
}, {
  id: 22,
  parentId: 19,
  title: 'Final Paperwork and Documents',
  start: new Date(year, month + 2, 24),
  end: new Date(year, month + 2, 28),
  progress: 0,
}];
export const dependencies = [{
  id: 1,
  predecessorId: 4,
  successorId: 5,
  type: 0,
}, {
  id: 2,
  predecessorId: 5,
  successorId: 7,
  type: 0,
}, {
  id: 3,
  predecessorId: 12,
  successorId: 13,
  type: 0,
}, {
  id: 4,
  predecessorId: 13,
  successorId: 14,
  type: 0,
}, {
  id: 5,
  predecessorId: 18,
  successorId: 20,
  type: 0,
}, {
  id: 6,
  predecessorId: 21,
  successorId: 22,
  type: 0,
}];
    
    window.exports = window.exports || {};
window.config = {
  transpiler: 'ts',
  typescriptOptions: {
    module: 'system',
    emitDecoratorMetadata: true,
    experimentalDecorators: true,
    jsx: 'react',
  },
  meta: {
    'react': {
      'esModule': true,
    },
    'typescript': {
      'exports': 'ts',
    },
    'devextreme/time_zone_utils.js': {
      'esModule': true,
    },
    'devextreme/localization.js': {
      'esModule': true,
    },
    'devextreme/viz/palette.js': {
      'esModule': true,
    },
    'openai': {
      'esModule': true,
    },
  },
  paths: {
    'npm:': 'https://cdn.jsdelivr.net/npm/',
    'bundles:': '../../../../bundles/',
    'externals:': '../../../../bundles/externals/',
  },
  defaultExtension: 'js',
  map: {
    'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js',
    'typescript': 'npm:typescript@4.2.4/lib/typescript.js',
    'jszip': 'npm:jszip@3.10.1/dist/jszip.min.js',
    'react': 'npm:react@17.0.2/umd/react.development.js',
    'react-dom': 'npm:react-dom@17.0.2/umd/react-dom.development.js',
    'prop-types': 'npm:prop-types/prop-types.js',
    'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js',
    'luxon': 'npm:luxon@3.4.4/build/global/luxon.min.js',
    'es6-object-assign': 'npm:es6-object-assign',
    'devextreme': 'npm:devextreme@link:../../packages/devextreme/artifacts/npm/devextreme/cjs',
    'devextreme-react': 'npm:devextreme-react@link:../../packages/devextreme-react/npm/cjs',
    'devextreme-quill': 'npm:devextreme-quill@1.7.6/dist/dx-quill.min.js',
    'devexpress-diagram': 'npm:devexpress-diagram@2.2.24/dist/dx-diagram.js',
    'devexpress-gantt': 'npm:devexpress-gantt@4.1.64/dist/dx-gantt.js',
    'inferno': 'npm:inferno@8.2.3/dist/inferno.min.js',
    'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
    'inferno-create-element': 'npm:inferno-create-element@8.2.3/dist/inferno-create-element.min.js',
    'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js',
    'inferno-hydrate': 'npm:inferno-hydrate/dist/inferno-hydrate.min.js',
    'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js',
    'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js',
    'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js',
    '@preact/signals-core': 'npm:@preact/signals-core@1.8.0/dist/signals-core.min.js',
    'devextreme-cldr-data': 'npm:devextreme-cldr-data@1.0.3',
    // SystemJS plugins
    'plugin-babel': 'npm:systemjs-plugin-babel@0.0.25/plugin-babel.js',
    'systemjs-babel-build': 'npm:systemjs-plugin-babel@0.0.25/systemjs-babel-browser.js',
    // Prettier
    'prettier/standalone': 'npm:prettier@2.8.8/standalone.js',
    'prettier/parser-html': 'npm:prettier@2.8.8/parser-html.js',
  },
  packages: {
    'devextreme': {
      defaultExtension: 'js',
    },
    'devextreme-react': {
      main: 'index.js',
    },
    'devextreme-react/common': {
      main: 'index.js',
    },
    'devextreme/events/utils': {
      main: 'index',
    },
    'devextreme/common/core/events/utils': {
      main: 'index',
    },
    'devextreme/localization/messages': {
      format: 'json',
      defaultExtension: 'json',
    },
    'devextreme/events': {
      main: 'index',
    },
    'es6-object-assign': {
      main: './index.js',
      defaultExtension: 'js',
    },
  },
  packageConfigPaths: [
    'npm:@devextreme/*/package.json',
  ],
  babelOptions: {
    sourceMaps: false,
    stage0: true,
    react: true,
  },
};
System.config(window.config);
// eslint-disable-next-line
const useTgzInCSB = ['openai'];
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
    
    export const currentDate = new Date(Date.now());
const month = currentDate.getMonth();
const year = currentDate.getFullYear();
export const tasks = [
  {
    id: 1,
    parentId: 0,
    title: 'Johnson Residence Construction Project',
    start: new Date(year, month - 1, 1),
    end: new Date(year, month - 1, 1),
    progress: 0,
  },
  {
    id: 2,
    parentId: 1,
    title: 'Planning and Pre-Construction Phase',
    start: new Date(year, month - 1, 1),
    end: new Date(year, month - 1, 1),
    progress: 0,
  },
  {
    id: 3,
    parentId: 2,
    title: 'Architectural Design and Site Planning',
    start: new Date(year, month - 1, 1),
    end: new Date(year, month - 1, 15),
    progress: 0,
  },
  {
    id: 4,
    parentId: 2,
    title: 'Engineering and Final Blueprint',
    start: new Date(year, month - 1, 8),
    end: new Date(year, month - 1, 15),
    progress: 0,
  },
  {
    id: 5,
    parentId: 2,
    title: 'City Permits and Contracts',
    start: new Date(year, month - 1, 15),
    end: new Date(year, month - 1, 18),
    progress: 0,
  },
  {
    id: 6,
    parentId: 1,
    title: 'Construction Phase',
    start: new Date(year, month - 1, 18),
    end: new Date(year, month - 1, 18),
    progress: 0,
  },
  {
    id: 7,
    parentId: 6,
    title: 'Grading and Excavation',
    start: new Date(year, month - 1, 18),
    end: new Date(year, month - 1, 22),
    progress: 0,
  },
  {
    id: 8,
    parentId: 6,
    title: 'Demolition and Removal',
    start: new Date(year, month - 1, 19),
    end: new Date(year, month - 1, 23),
    progress: 0,
  },
  {
    id: 9,
    parentId: 6,
    title: 'Foundation and Concrete ',
    start: new Date(year, month - 1, 22),
    end: new Date(year, month - 1, 28),
    progress: 0,
  },
  {
    id: 10,
    parentId: 6,
    title: 'Rough Framing and Carpentery',
    start: new Date(year, month - 1, 25),
    end: new Date(year, month, 5),
    progress: 0,
  },
  {
    id: 11,
    parentId: 6,
    title: 'Inspection (Structure)',
    start: new Date(year, month, 5),
    end: new Date(year, month, 5),
    progress: 0,
  },
  {
    id: 12,
    parentId: 6,
    title: 'Electrical Rough-in',
    start: new Date(year, month, 6),
    end: new Date(year, month, 19),
    progress: 0,
  },
  {
    id: 13,
    parentId: 6,
    title: 'Plumbing Rough-in',
    start: new Date(year, month, 19),
    end: new Date(year, month, 19),
    progress: 0,
  },
  {
    id: 14,
    parentId: 6,
    title: 'Heating and A/C',
    start: new Date(year, month, 19),
    end: new Date(year, month, 26),
    progress: 0,
  },
  {
    id: 15,
    parentId: 6,
    title: 'Drywall',
    start: new Date(year, month, 25),
    end: new Date(year, month + 1, 10),
    progress: 0,
  },
  {
    id: 16,
    parentId: 6,
    title: 'Painting (Exterior)',
    start: new Date(year, month + 1, 7),
    end: new Date(year, month + 1, 21),
    progress: 0,
  },
  {
    id: 17,
    parentId: 6,
    title: 'Interior Carpentery (Interior)',
    start: new Date(year, month + 1, 17),
    end: new Date(year, month + 1, 28),
    progress: 0,
  },
  {
    id: 18,
    parentId: 6,
    title: 'Flooring and Interior Paint',
    start: new Date(year, month + 1, 26),
    end: new Date(year, month + 2, 9),
    progress: 0,
  },
  {
    id: 19,
    parentId: 1,
    title: 'Final Phase',
    start: new Date(year, month + 2, 9),
    end: new Date(year, month + 2, 9),
    progress: 0,
  },
  {
    id: 20,
    parentId: 19,
    title: 'Review-Punch List',
    start: new Date(year, month + 2, 9),
    end: new Date(year, month + 2, 23),
    progress: 0,
  },
  {
    id: 21,
    parentId: 19,
    title: 'Final Inspection',
    start: new Date(year, month + 2, 24),
    end: new Date(year, month + 2, 24),
    progress: 0,
  },
  {
    id: 22,
    parentId: 19,
    title: 'Final Paperwork and Documents',
    start: new Date(year, month + 2, 24),
    end: new Date(year, month + 2, 28),
    progress: 0,
  },
];
export const dependencies = [
  {
    id: 1,
    predecessorId: 4,
    successorId: 5,
    type: 0,
  },
  {
    id: 2,
    predecessorId: 5,
    successorId: 7,
    type: 0,
  },
  {
    id: 3,
    predecessorId: 12,
    successorId: 13,
    type: 0,
  },
  {
    id: 4,
    predecessorId: 13,
    successorId: 14,
    type: 0,
  },
  {
    id: 5,
    predecessorId: 18,
    successorId: 20,
    type: 0,
  },
  {
    id: 6,
    predecessorId: 21,
    successorId: 22,
    type: 0,
  },
];
    
    <!DOCTYPE html>
<html lang="en">
  <head>
    <title>DevExtreme Demo</title>
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" />
    <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/25.1.6/css/dx.light.css" />
    <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/25.1.6/css/dx-gantt.min.css" />
    <link rel="stylesheet" type="text/css" href="styles.css" />
    <script src="https://cdn.jsdelivr.net/npm/core-js@2.6.12/client/shim.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/systemjs@0.21.3/dist/system.js"></script>
    <script type="text/javascript" src="config.js"></script>
    <script type="text/javascript">
      System.import("./index.tsx");
    </script>
  </head>
  <body class="dx-viewport">
    <div class="demo-container">
      <div id="app"></div>
    </div>
  </body>
</html>
    
    #gantt {
  height: 700px;
}
.options {
  margin-bottom: 20px;
  padding: 20px;
  background-color: rgba(191, 191, 191, 0.15);
  position: relative;
}
.caption {
  font-size: 18px;
  font-weight: 500;
}
.option {
  margin-top: 10px;
  margin-right: 40px;
  display: inline-block;
}
.option:last-child {
  margin-right: 0;
}
    
                The Gantt supports the following dependency validation rules:
- Finish to Start (FS) - A successor task's start point should be equal or later than the preceding task's end point.
- Start to Start (SS) - A successor task's start point should be equal or later than the preceding task's start point.
- Finish to Finish (FF) - A successor task's end point should be equal or later than the preceding task's end point.
- Start to Finish (SF) - A successor task's end point should be equal or later than a preceding task's start point.
The Gantt also has the autoUpdateParentTasks property that enables validation for parent-child relationship:
- A parent task's duration equals a summary duration of its child tasks.
- A parent task and its first child starts at the same time.
- A parent task and its last child ends at the same time.
- A parent task's progress is a summary progress of its child tasks.
The Gantt processes changes in task values before they are saved to a database. The component displays a popup window with a list of available actions if an error can be handled in several ways.