components: Add normalizeArrowKey

packages/components/src/utils/keyboard.js

@@ -0,0 +1,28 @@
+/**
+ * WordPress dependencies
+ */
+import { RIGHT, UP, DOWN, LEFT } from '@wordpress/keycodes';
+
+/**
+ * @type {number[]}
+ */
+const arrowKeys = [ RIGHT, UP, DOWN, LEFT ];
+
+/**
+ * Normalizes the 'key' property of a KeyboardEvent in IE/Edge
+ *
+ * Source:
+ * https://github.com/downshift-js/downshift/blob/a71005bd879d05d7dcb892d1e0dc5c6ca74e9d39/src/utils.js#L279
+ *
+ * @param {import('react').KeyboardEvent} event A keyboardEvent object
+ *
+ * @return {string} The keyboard key
+ */
+export function normalizeArrowKey( event ) {
+	const { key, keyCode } = event;
+
+	if ( arrowKeys.includes( keyCode ) && key.indexOf( 'Arrow' ) !== 0 ) {
+		return `Arrow${ key }`;
+	}
+	return key;
+}

packages/components/src/utils/test/keyboard.js

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+/**
+ * WordPress dependencies
+ */
+import { RIGHT, UP, DOWN, LEFT, SPACE } from '@wordpress/keycodes';
+
+/**
+ * Internal dependencies
+ */
+import { normalizeArrowKey } from '../keyboard';
+
+describe( 'normalizeArrowKey', () => {
+	it.each`
+		keyCode    | key               | normalized
+		${ RIGHT } | ${ 'Right' }      | ${ 'ArrowRight' }
+		${ UP }    | ${ 'Up' }         | ${ 'ArrowUp' }
+		${ DOWN }  | ${ 'Down' }       | ${ 'ArrowDown' }
+		${ LEFT }  | ${ 'Left' }       | ${ 'ArrowLeft' }
+		${ RIGHT } | ${ 'ArrowRight' } | ${ 'ArrowRight' }
+		${ UP }    | ${ 'ArrowUp' }    | ${ 'ArrowUp' }
+		${ DOWN }  | ${ 'ArrowDown' }  | ${ 'ArrowDown' }
+		${ LEFT }  | ${ 'ArrowLeft' }  | ${ 'ArrowLeft' }
+		${ SPACE } | ${ 'Space' }      | ${ 'Space' }
+	`(
+		'should return $normalized for $key with keycode $keyCode',
+		( { keyCode, key, normalized } ) => {
+			const e = new window.KeyboardEvent( 'keydown', {
+				key,
+				keyCode,
+			} );
+
+			expect( normalizeArrowKey( e ) ).toEqual( normalized );
+		}
+	);
+} );