Oat Upload

Dropzone, file previews, validation, removal, and progress for native <input type="file"> in Oat UI.

Oat Upload is a small, zero-runtime-dependency extension for Oat. It keeps the native file input as the source of truth and adds progressive behavior around it:

• drag and drop over a semantic file input
• image and file previews
• remove selected files before submit
• size, type, and count validation
• progress via native <progress>
• form-friendly file syncing where the browser supports DataTransfer
• events for app code: ot-upload-change and ot-upload-error

Without JavaScript, users still get a regular <input type="file">. With JavaScript, <ot-upload> builds the richer upload surface.

Install

With npm:

npm install @globus.studio/oat-upload

import '@globus.studio/oat-upload/css';
import '@globus.studio/oat-upload';

From a CDN:

<link rel="stylesheet" href="https://oat.ink/oat.min.css">
<link rel="stylesheet" href="https://unpkg.com/@globus.studio/oat-upload@0.1.1/dist/oat-upload.min.css">
<script src="https://oat.ink/oat.min.js" defer></script>
<script src="https://unpkg.com/@globus.studio/oat-upload@0.1.1/dist/oat-upload.min.js" defer></script>

Basic Usage

<ot-upload max-size="5242880" max-files="5">
  <input type="file" name="attachments" multiple accept="image/*,.pdf">
</ot-upload>

That is enough. Oat Upload creates the dropzone, preview list, status output, and progress element.

Custom Markup

Use data-upload-* parts when you want to control the HTML.

<ot-upload max-size="5242880" max-files="3">
  <input id="files" type="file" name="files" multiple accept="image/*,.pdf">

  <label data-upload-dropzone for="files">
    <strong>Drop files here</strong>
    <small class="text-light">Images or PDF, up to 5 MB each.</small>
  </label>

  <output data-upload-error role="status" aria-live="polite"></output>
  <ul data-upload-list aria-label="Selected files"></ul>
  <progress data-upload-progress max="100" value="0" hidden></progress>
  <output data-upload-status aria-live="polite"></output>
</ot-upload>

Validation

Validation reads from the native input first, then from <ot-upload> attributes.

<ot-upload accept="image/*,.pdf" max-size="5242880" max-files="5">
  <input type="file" multiple>
</ot-upload>

Attribute	Element	Description
accept	input, ot-upload	Comma-separated extensions or MIME types. Supports image/*.
max-size	ot-upload	Max bytes per file.
max-files	ot-upload	Max accepted files.
multiple	input	Allows more than one file. Without it, new selection replaces the previous file.
disabled	input, ot-upload	Disables drop and picker behavior.

Rejected files trigger ot-upload-error and are not added to the selected list.

Progress

Use the native progress element generated by the component or provide your own with data-upload-progress.

const upload = document.querySelector('ot-upload');

upload.setProgress(0);
upload.setProgress(65);
upload.setProgress(100);

Passing null or calling resetProgress() hides the progress element.

upload.resetProgress();

Events

const upload = document.querySelector('ot-upload');

upload.addEventListener('ot-upload-change', (event) => {
  console.log(event.detail.files);
  console.log(event.detail.added);
  console.log(event.detail.removed);
});

upload.addEventListener('ot-upload-error', (event) => {
  console.log(event.detail.reason);
  console.log(event.detail.message);
});

ot-upload-change detail:

Property	Description
files	Current accepted files.
added	Files added by the current operation.
removed	Files removed by the current operation.
rejected	Rejected files from the current operation.

ot-upload-error detail:

Property	Description
file	Rejected file, when available.
reason	type, size, count, or disabled.
message	Human-readable message.

API

const upload = document.querySelector('ot-upload');

upload.files;              // accepted files
upload.addFiles(files);    // FileList or File[]
upload.remove(fileOrId);   // File, item id, or index
upload.clear();            // remove all files
upload.setProgress(42);    // update native progress
upload.resetProgress();    // hide progress

Development

npm install
npm run check

npm run check builds dist/ and runs the DOM test suite.

Publishing

npm run check
npm publish --dry-run
npm publish

The package is configured for public scoped npm publishing with publishConfig.access.

License

MIT.