fix(inputSelect) Improving inputSelect component usability (#26)

Packages/ohif-core/client/components/base/mixins/select2.js

@@ -99,8 +99,9 @@ OHIF.mixins.select2 = new OHIF.Mixin({
                 // Get the focusable elements
                 const elements = [];
                 const $select2 = component.$element.nextAll('.select2:first');
+                const $select2Selection = $select2.find('.select2-selection');
                 elements.push(component.$element[0]);
-                elements.push($select2.find('.select2-selection')[0]);
+                elements.push($select2Selection[0]);
 
                 // Attach focus and blur handlers to focusable elements
                 $(elements).on('focus', event => {
@@ -130,6 +131,32 @@ OHIF.mixins.select2 = new OHIF.Mixin({
                     }
                 });
 
+                // Handle dropdown opening when focusing the selection element
+                $select2Selection.on('keydown ', event => {
+                    const skipKeys = new Set([8, 9, 12, 16, 17, 18, 20, 27, 46, 91, 93]);
+                    const functionKeysRegex = /F[0-9]([0-9])?$/;
+                    const isFunctionKey = functionKeysRegex.test(event.key);
+                    if (skipKeys.has(event.which) || isFunctionKey) {
+                        return;
+                    }
+
+                    event.preventDefault();
+                    event.stopPropagation();
+
+                    // Open the select2 dropdown
+                    instance.component.$element.select2('open');
+
+                    // Check if the pressed key will produce a character
+                    const searchSelector = '.select2-search__field';
+                    const $search = component.select2Instance.$dropdown.find(searchSelector);
+                    const isChar = OHIF.ui.isCharacterKeyPress(event);
+                    const char = event.key;
+                    if ($search.length && isChar && char.length === 1) {
+                        // Event needs to be triggered twice to work properly with this plugin
+                        $search.val(char).trigger('input').trigger('input');
+                    }
+                });
+
                 // Set select2 as initialized
                 instance.isInitialized = true;
             };
@@ -177,9 +204,10 @@ OHIF.mixins.select2 = new OHIF.Mixin({
                 }
 
                 const $searchInput = $container.find('.select2-search__field');
-                $searchInput.on('keydown.focusOnEsc', event => {
+                $searchInput.on('keydown.focusOnFinish', event => {
-                    if (event.which === 27) {
+                    const keys = new Set([9, 13, 27]);
-                        $searchInput.off('keydown.focusOnEsc');
+                    if (keys.has(event.which)) {
+                        $searchInput.off('keydown.focusOnFinish');
                         instance.component.$element.focus();
                     }
                 });

Packages/ohif-core/client/lib/ui.js

@@ -68,3 +68,23 @@ OHIF.ui.getScrollbarSize = () => {
 
     return [(w1 - w2), (h1 - h2)];
 };
+
+/**
+ * Check if the pressed key combination will result in a character input
+ * Got from https://stackoverflow.com/questions/4179708/how-to-detect-if-the-pressed-key-will-produce-a-character-inside-an-input-text
+ *
+ * @returns {Boolean} Wheter the pressed key combination will input a character or not
+ */
+OHIF.ui.isCharacterKeyPress = event => {
+    if (typeof event.which === 'undefined') {
+        // This is IE, which only fires keypress events for printable keys
+        return true;
+    } else if (typeof event.which === 'number' && event.which > 0) {
+        // In other browsers except old versions of WebKit, event.which is
+        // only greater than zero if the keypress is a printable key.
+        // We need to filter out backspace and ctrl/alt/meta key combinations
+        return !event.ctrlKey && !event.metaKey && !event.altKey && event.which !== 8;
+    }
+
+    return false;
+};