In this Hasty Treat, Scott and Wes talk about JavaScript’s drag and drop API — how it works, concerns, best practices, and more!

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Show Notes

04:45 - What is it?

• Drag and drop is really for desktop apps
• You can drag and drop anything from any browser to any browser
• The important thing here is that this is a set of browser standards that allow different apps to communicate

07:50 - How to implement

1. Make an element draggable
2. Listen on elements for drag events
   • The events bubble up, so you can listen on the parent element as items are added/removed

09:06 - DataTransfer API

• You can store anything you want in it
• getData / setData API
• Reference strings

11:35 - Accepting drops

• When you dragOver, you need to preventDefault()
• Calling the preventDefault() method during both a dragEnter and dragOver event will indicate that a drop is allowed at that location

13:01 - Drop Image

• Set whatever you want

16:00 - Drop Effect

• What does it look like when you drop it? Does it go back?
• dataTransfer.effectAllowed
• e.dataTransfer.setDragImage(nothing, 0, 0);

18:02 - Security concerns

20:34 - Shortcomings:

• Edge cases out the WAZOO
  • Margin caused dragout events
  • Lots of if statements
• It’s up to you to do EVERYTHING
  • CSS, classes, hover styles, etc.
• Accessibility
  • Inaccessible by default, unless using mouse keys
  • Have to announce everything
• Mobile

26:14 - Lbs

• Transmat API

Links

• Figma
• Notion
• Missive

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