Svelte Gantt Demos

• Online demo: https://dhtmlx.com/svelte/demos/gantt/#/base/default
• Code of demos: https://github.com/web-widgets/svelte-gantt-demos
• Minimal project: https://svelte.dev/repl/f2f23aea85094858a36d3c1712282dfc

Supported functionality

Common with DHTMLX Gantt

• adding/editing/deleting tasks and links
• tasks, projects and milestones
• configurable scales and grids
• configurable tooltips
• time markers

Unique features

• svelte widgets can be used for tasks rendering, tooltips and form controls
• all configuration properties are reactive
• full svelte sources are provided

Usage

Installation

• add library to your svelte project

npm install @dhtmlx/trial-svelte-gantt

This will install trial version, for commercial one, use "@dhx/svelte-gantt"

• place Gantt tag into the desired page

import { Gantt, DefaultTheme } from "@dhtmlx/trial-svelte-gantt";

export default function GanttBasic() {
	return (
		<DefaultTheme>
			<Gantt />
		</DefaultTheme>
	);
}

You can check the demo of mininal project here - https://svelte.dev/repl/f2f23aea85094858a36d3c1712282dfc

Source code of the gantt can be checked in node_modules/@dhtmlx/trial-svelte-gantt/src

Themes

Package contains two predefined themes - Default and Material.

You can apply theme by wrapping Gantt into DefaultTheme or MaterialTheme tags

<div>
	<DefaultTheme>
		<Gantt />
	</DefaultTheme>
	<MaterialTheme>
		<Gantt />
	</MaterialTheme>
</div>

or you can just add theme tag on the page and add skin class to one of Gantt's parent tags

<div>
	<DefaultTheme />
	<MaterialTheme />

	<div class="wx-default">
		<Gantt />
	</div>
	<div class="wx-material">
		<Gantt />
	</div>
</div>

Initialization

You can define scales/columns/tasks/links during Gantt initialization

<Gantt {scales} {columns} {tasks} {links} />

where data may look like next

const scales = [
	{ unit: "month", step: 1, format: "MMMM yyy" },
	{ unit: "day", step: 1, format: "d" },
];

const columns = [
	{ name: "text", label: "Task name", width: "100%" },
	{ name: "start", label: "Start time", align: "center" },
	{ name: "duration", label: "Duration", width: "70px", align: "center" },
	{ name: "add-task", label: "", width: "50px", align: "center" },
];

const tasks = [
	{
		id: 1,
		open: true,
		start_date: "2020-11-06",
		duration: 8,
		text: "svelte Gantt Widget",
		progress: 60,
		type: "project",
	},
	{
		id: 2,
		parent: 1,
		start_date: "2020-11-06",
		duration: 4,
		text: "Lib-Gantt",
		progress: 80,
	},
];

const links = [{ source: 2, target: 1, type: 0 }];

Integration with backend

Check https://github.com/web-widgets/svelte-gantt-demos/blob/master/src/GanttBackend.svelte

Code defines the action handler through save event. This event will be triggered on any update and may be used to save changes to the persistent storage.

In the above example, the RestDataProvider is used https://github.com/web-widgets/gantt-data-provider/blob/master/src/providers/rest.ts You are not limited to this solution, though, and can extend the provided class or define a custom handler.

We provide 2 demo backends, with nodejs and go

• https://github.com/web-widgets/gantt-go
• https://github.com/web-widgets/gantt-node

again, you are not limited to this solution. The above RestDataProvider can work with any REST like service and you can implement a fully custom solution ( sockets, graphql, etc. ) through custom save event.

Templates

The next elements can be customized through templates

• task text
• sidebar form

check https://github.com/web-widgets/svelte-gantt-demos/blob/master/src/GanttText.svelte

• tooltip content

check https://github.com/web-widgets/svelte-gantt-demos/blob/master/src/GanttTooltips.svelte

API

Properties

// templates for different elements of gantt
let templates = {};
// array of markers
let markers = [];
// supported task types
let taskTypes = ["task", "project", "milestone"];
// tasks data
let tasks = [];
// links data
let links = [];
// time scales configuration
let scales = [
	{ unit: "month", step: 1, format: "MMMM yyy" },
	{ unit: "day", step: 1, format: "d" },
];
// grid configuration
let columns = [
	{ name: "text", label: "Task name", width: "100%" },
	{ name: "add-task", label: "", width: "50px", align: "center" },
];
// time scale start
let start = null;
// time scale end
let end = null;
// width of scale cell
let cellWidth = 100;
// height of chart bar
let cellHeight = 38;
// height of scale cell
let scaleHeight = 30;
// readonly mode flag
let readonly = false;
// show or hide grid
let grid = true;
// show or hide tooltips
let tooltip = null;
// show or hide borders in the chart area
let borders = "full";

Events

// will be called on any action in the Gantt
let actions = null;
// will be called on any data modification in the Gantt
let save = null;

Actions

Data modifications ( both action and save events )

• add-link
• update-link
• delete-link
• add-task
• update-task
• delete-task

UI State ( action event )

• data-request
• hide-details
• move-task
• scroll-chart
• select-task
• show-details
• task-toggle
• update-task-time

Example of event usage

function handler({ action, obj, id }) {
	if (action === "select-task") console.log(`Task ${id} was selected`);
}

<Gantt on:action={handler} />;

Methods

let store;

<Gantt bind:store />;

and now you can use store's API to get or modify data.

interface IStore {
	getTask(id: number): GanttItemData;
	updateTask(id: number, obj: any, noSave: boolean): void;
	updateLink(id: number, obj: any, noSave: boolean): void;
	action(
		id: number,
		action: string,
		obj: StringHash<any>,
		noSave?: boolean
	): number;
}

action method can be used to trigger any of above actions

store.action(taskId, "tasks-toggle");
store.action(linkId, "delete-link");
store.action(null, "add-link", { source: 1, target 2, type: 0 });