Flowy

A javascript library to create pretty flowcharts with ease ✨

Dribbble | Twitter | Live demo

Flowy makes creating WebApps with flowchart functionality an incredibly simple task. Build automation software, mind mapping tools, or simple programming platforms in minutes by implementing the library into your project.

You can support this project (and many others) through GitHub Sponsors! ❤️

Made by Alyssa X

Table of contents

• Features
• Installation
• Running Flowy
  • Initialization
  • Example
• Callbacks
  • On grab
  • On release
  • On snap
  • On rearrange
• Methods
  • Get the flowchart data
  • Import the flowchart data
  • Delete all blocks

Features

Currently, Flowy supports the following:

• Responsive drag and drop
• Automatic snapping
• Automatic scrolling
• Block rearrangement
• Delete blocks
• Automatic block centering
• Conditional snapping
• Conditional block removal
• Import saved files
• Mobile support
• Vanilla javascript (no dependencies)
• npm install

You can suggest new features here

Installation

Adding Flowy to your WebApp is incredibly simple:

1. Link flowy.min.js and flowy.min.css to your project. Through jsDelivr:

<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/alyssaxuu/flowy/flowy.min.css"> 
<script src="https://cdn.jsdelivr.net/gh/alyssaxuu/flowy/flowy.min.js"></script>

2. Create a canvas element that will contain the flowchart (for example, <div id="canvas"></div>)
3. Create the draggable blocks with the .create-flowy class (for example, <div class="create-flowy">Grab me</div>)

Running Flowy

Initialization

flowy(canvas, ongrab, onrelease, onsnap, onrearrange, spacing_x, spacing_y);

Parameter	Type	Description
canvas	javascript DOM element	The element that will contain the blocks
ongrab	function (optional)	Function that gets triggered when a block is dragged
onrelease	function (optional)	Function that gets triggered when a block is released
onsnap	function (optional)	Function that gets triggered when a block snaps with another one
onrearrange	function (optional)	Function that gets triggered when blocks are rearranged
spacing_x	integer (optional)	Horizontal spacing between blocks (default 20px)
spacing_y	integer (optional)	Vertical spacing between blocks (default 80px)

To define the blocks that can be dragged, you need to add the class .create-flowy

Example

HTML

<div class="create-flowy">The block to be dragged</div>
<div id="canvas"></div>

Javascript

var spacing_x = 40;
var spacing_y = 100;
// Initialize Flowy
flowy(document.getElementById("canvas"), onGrab, onRelease, onSnap, onRearrange, spacing_x, spacing_y);
function onGrab(block){
	// When the user grabs a block
}
function onRelease(){
	// When the user releases a block
}
function onSnap(block, first, parent){
	// When a block snaps with another one
}
function onRearrange(block, parent){
	// When a block is rearranged
}

Callbacks

In order to use callbacks, you need to add the functions when initializing Flowy, as explained before.

On grab

function onGrab(block){
	// When the user grabs a block
}

Gets triggered when a user grabs a block with the class create-flowy

Parameter	Type	Description
block	javascript DOM element	The block that has been grabbed

On release

function onRelease(){
	// When the user lets go of a block
}

Gets triggered when a user lets go of a block, regardless of whether it attaches or even gets released in the canvas.

On snap

function onSnap(block, first, parent){
	// When a block can attach to a parent
	return true;
}

Gets triggered when a block can attach to another parent block. You can either prevent the attachment, or allow it by using return true;

Parameter	Type	Description
block	javascript DOM element	The block that has been grabbed
first	boolean	If true, the block that has been dragged is the first one in the canvas
parent	javascript DOM element	The parent the block can attach to

On rearrange

function onRearrange(block, parent){
	// When a block is rearranged
	return true;
}

Gets triggered when blocks are rearranged and are dropped anywhere in the canvas, without a parent to attach to. You can either allow the blocks to be deleted, or prevent it and thus have them re-attach to their previous parent using return true;

Parameter	Type	Description
block	javascript DOM element	The block that has been grabbed
parent	javascript DOM element	The parent the block can attach to

Methods

Get the flowchart data

// As an object
flowy.output();
// As a JSON string
JSON.stringify(flowy.output());

The JSON object that gets outputted looks like this:

{
	"html": "",
	"blockarr": [],
	"blocks": [
		{
			"id": 1,
			"parent": 0,
			"data": [
				{
				"name": "blockid",
				"value": "1"
				}
			],
			"attr": [
				{
				"id": "block-id",
				"class": "block-class"
				}
			]
		}
	]
}

Here's what each property means:

Key	Value type	Description
html	string	Contains the canvas data
blockarr	array	Contains the block array generated by the library (for import purposes)
blocks	array	Contains the readable block array
id	integer	Unique value that identifies a block
parent	integer	The id of the parent a block is attached to (-1 means the block has no parent)
data	array of objects	An array of all the inputs within a certain block
name	string	The name attribute of the input
value	string	The value attribute of the input
attr	array of objects	Contains all the data attributes of a certain block

Import the flowchart data

flowy.import(output)

Allows you to import entire flowcharts initially exported using the previous method, flowy.output()

Parameter	Type	Description
output	javascript DOM element	The data from flowy.output()

Warning

This method accepts raw HTML and does not sanitize it, therefore this method is vulnerable to XSS. The only safe use for this method is when the input is absolutely trusted, if the input is not to be trusted the use this method can introduce a vulnerability in your system.

Delete all blocks

To remove all blocks at once use:

flowy.deleteBlocks()

Currently there is no method to individually remove blocks. The only way to go about it is by splitting branches manually.

Feel free to reach out to me through email at hi@alyssax.com or on Twitter if you have any questions or feedback! Hope you find this useful 💜