Drop Babel in favor of esm and TypeScript (#1726)

To get some meaningful errors during feature development, I thought it'd be useful to use TypeScript on `features.js` only, hoping to keep it contained to that file.

@sindresorhus suggested we just extend it the whole extension and maybe that can be done incrementally, without having to necessarily use types on everything.

1 files changed, 66 insertions, 0 deletions

diff --git a/source/features/upload-button.tsx b/source/features/upload-button.tsx
new file mode 100644
index 00000000..02f08cb9
--- /dev/null
+++ b/source/features/upload-button.tsx
@@ -0,0 +1,66 @@
+import {React} from 'dom-chef/react';
+import select from 'select-dom';
+import delegate from 'delegate';
+import onetime from 'onetime';
+import features from '../libs/features';
+import observeEl from '../libs/simplified-element-observer';
+import {metaKey} from '../libs/utils';
+import * as icons from '../libs/icons';
+
+function addButtons() {
+	for (const toolbar of select.all('form:not(.rgh-has-upload-field) markdown-toolbar')) {
+		const form = toolbar.closest('form');
+		if (!select.exists('.js-manual-file-chooser[type=file]', form)) {
+			continue;
+		}
+		observeEl(toolbar, function () {
+			const toolbarGroup = select('.toolbar-group:last-child', toolbar);
+			if (toolbarGroup) {
+				toolbarGroup.append(
+					<button type="button" class="toolbar-item rgh-upload-btn tooltipped tooltipped-nw" aria-label="Upload attachments">
+						{icons.cloudUpload()}
+					</button>
+				);
+				form.classList.add('rgh-has-upload-field');
+				this.disconnect();
+			}
+		});
+	}
+}
+
+function triggerUploadUI({target}) {
+	target
+		.closest('form')
+		.querySelector('.js-manual-file-chooser') // Find <input [type=file]>
+		.click(); // Open UI
+}
+
+function handleKeydown(event) {
+	if (event[metaKey] && event.key === 'u') {
+		triggerUploadUI(event);
+		event.preventDefault();
+	}
+}
+
+const listenOnce = onetime(() => {
+	delegate('.rgh-has-upload-field', 'keydown', handleKeydown);
+	delegate('.rgh-upload-btn', 'click', triggerUploadUI);
+});
+
+function init() {
+	addButtons();
+	listenOnce();
+}
+
+features.add({
+	id: 'upload-button',
+	include: [
+		features.isPR,
+		features.isIssue,
+		features.isNewIssue,
+		features.isCompare,
+		features.isCommit
+	],
+	load: features.onAjaxedPages,
+	init
+});