Hotkey util (#1270)

* Create HotkeyUtil

* Create tests

* Use HotkeyUtil

* Fix issues

6 files changed, 482 insertions, 112 deletions

diff --git a/ext/bg/js/settings/keyboard-mouse-input-field.js b/ext/bg/js/settings/keyboard-mouse-input-field.js
index d48b130f..94709313 100644
--- a/ext/bg/js/settings/keyboard-mouse-input-field.js
+++ b/ext/bg/js/settings/keyboard-mouse-input-field.js
@@ -17,6 +17,7 @@
 
 /* global
  * DocumentUtil
+ * HotkeyUtil
  */
 
 class KeyboardMouseInputField extends EventDispatcher {
@@ -25,15 +26,7 @@ class KeyboardMouseInputField extends EventDispatcher {
         this._inputNode = inputNode;
         this._mouseButton = mouseButton;
         this._isPointerTypeSupported = isPointerTypeSupported;
-        this._keySeparator = ' + ';
-        this._inputNameMap = new Map(DocumentUtil.getModifierKeys(os));
-        this._modifierPriorities = new Map([
-            ['meta', -4],
-            ['ctrl', -3],
-            ['alt', -2],
-            ['shift', -1]
-        ]);
-        this._mouseInputNamePattern = /^mouse(\d+)$/;
+        this._hotkeyUtil = new HotkeyUtil(os);
         this._eventListeners = new EventListenerCollection();
         this._key = null;
         this._modifiers = [];
@@ -93,74 +86,14 @@ class KeyboardMouseInputField extends EventDispatcher {
     // Private
 
     _sortModifiers(modifiers) {
-        const pattern = this._mouseInputNamePattern;
-        const keyPriorities = this._modifierPriorities;
-        const modifierInfos = modifiers.map((modifier, index) => {
-            const match = pattern.exec(modifier);
-            if (match !== null) {
-                return [modifier, 1, Number.parseInt(match[1], 10), index];
-            } else {
-                let priority = keyPriorities.get(modifier);
-                if (typeof priority === 'undefined') { priority = 0; }
-                return [modifier, 0, priority, index];
-            }
-        });
-        modifierInfos.sort((a, b) => {
-            let i = a[1] - b[1];
-            if (i !== 0) { return i; }
-
-            i = a[2] - b[2];
-            if (i !== 0) { return i; }
-
-            i = a[0].localeCompare(b[0], 'en-US'); // Ensure an invariant culture
-            if (i !== 0) { return i; }
-
-            i = a[3] - b[3];
-            return i;
-        });
-        return modifierInfos.map(([modifier]) => modifier);
+        return this._hotkeyUtil.sortModifiers(modifiers);
     }
 
     _updateDisplayString() {
-        let displayValue = '';
-        let first = true;
-        for (const modifier of this._modifiers) {
-            const {name} = this._getModifierName(modifier);
-            if (first) {
-                first = false;
-            } else {
-                displayValue += this._keySeparator;
-            }
-            displayValue += name;
-        }
-        if (this._key !== null) {
-            if (!first) { displayValue += this._keySeparator; }
-            displayValue += this._getDisplayKey(this._key);
-        }
+        const displayValue = this._hotkeyUtil.getInputDisplayValue(this._key, this._modifiers);
         this._inputNode.value = displayValue;
     }
 
-    _getDisplayKey(key) {
-        if (typeof key === 'string') {
-            if (key.length === 4 && key.startsWith('Key')) {
-                key = key.substring(3);
-            }
-        }
-        return key;
-    }
-
-    _getModifierName(modifier) {
-        const pattern = this._mouseInputNamePattern;
-        const match = pattern.exec(modifier);
-        if (match !== null) {
-            return {name: `Mouse ${match[1]}`, type: 'mouse'};
-        }
-
-        let name = this._inputNameMap.get(modifier);
-        if (typeof name === 'undefined') { name = modifier; }
-        return {name, type: 'key'};
-    }
-
     _getModifierKeys(e) {
         const modifiers = new Set(DocumentUtil.getActiveModifiers(e));
         // https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/metaKey
diff --git a/ext/bg/js/settings/scan-inputs-simple-controller.js b/ext/bg/js/settings/scan-inputs-simple-controller.js
index 9e7eb5fc..01f044c2 100644
--- a/ext/bg/js/settings/scan-inputs-simple-controller.js
+++ b/ext/bg/js/settings/scan-inputs-simple-controller.js
@@ -16,7 +16,7 @@
  */
 
 /* global
- * DocumentUtil
+ * HotkeyUtil
  * ScanInputsController
  * api
  */
@@ -27,7 +27,7 @@ class ScanInputsSimpleController {
         this._middleMouseButtonScan = null;
         this._mainScanModifierKeyInput = null;
         this._mainScanModifierKeyInputHasOther = false;
-        this._os = null;
+        this._hotkeyUtil = new HotkeyUtil();
     }
 
     async prepare() {
@@ -35,7 +35,7 @@ class ScanInputsSimpleController {
         this._mainScanModifierKeyInput = document.querySelector('#main-scan-modifier-key');
 
         const {platform: {os}} = await api.getEnvironmentInfo();
-        this._os = os;
+        this._hotkeyUtil.os = os;
 
         this._mainScanModifierKeyInputHasOther = false;
         this._populateSelect(this._mainScanModifierKeyInput, this._mainScanModifierKeyInputHasOther);
@@ -106,9 +106,12 @@ class ScanInputsSimpleController {
 
     _populateSelect(select, hasOther) {
         const modifierKeys = [
-            {value: 'none', name: 'No key'},
-            ...DocumentUtil.getModifierKeys(this._os).map(([value, name]) => ({value, name}))
+            {value: 'none', name: 'No key'}
         ];
+        for (const value of ['alt', 'ctrl', 'shift', 'meta']) {
+            const name = this._hotkeyUtil.getModifierDisplayValue(value);
+            modifierKeys.push({value, name});
+        }
 
         if (hasOther) {
             modifierKeys.push({value: 'other', name: 'Other'});
diff --git a/ext/bg/settings2.html b/ext/bg/settings2.html
index 08f9ebef..65948b75 100644
--- a/ext/bg/settings2.html
+++ b/ext/bg/settings2.html
@@ -3060,6 +3060,7 @@
 <script src="/mixed/js/document-focus-controller.js"></script>
 <script src="/mixed/js/document-util.js"></script>
 <script src="/mixed/js/dom-data-binder.js"></script>
+<script src="/mixed/js/hotkey-util.js"></script>
 <script src="/mixed/js/html-template-collection.js"></script>
 <script src="/mixed/js/object-property-accessor.js"></script>
 <script src="/mixed/js/panel-element.js"></script>
diff --git a/ext/mixed/js/document-util.js b/ext/mixed/js/document-util.js
index 0c0a2153..513a0c05 100644
--- a/ext/mixed/js/document-util.js
+++ b/ext/mixed/js/document-util.js
@@ -305,42 +305,6 @@ class DocumentUtil {
         return true;
     }
 
-    static getModifierKeys(os) {
-        switch (os) {
-            case 'win':
-                return [
-                    ['alt', 'Alt'],
-                    ['ctrl', 'Ctrl'],
-                    ['shift', 'Shift'],
-                    ['meta', 'Windows']
-                ];
-            case 'mac':
-                return [
-                    ['alt', 'Opt'],
-                    ['ctrl', 'Ctrl'],
-                    ['shift', 'Shift'],
-                    ['meta', 'Cmd']
-                ];
-            case 'linux':
-            case 'openbsd':
-            case 'cros':
-            case 'android':
-                return [
-                    ['alt', 'Alt'],
-                    ['ctrl', 'Ctrl'],
-                    ['shift', 'Shift'],
-                    ['meta', 'Super']
-                ];
-            default: // 'unknown', etc
-                return [
-                    ['alt', 'Alt'],
-                    ['ctrl', 'Ctrl'],
-                    ['shift', 'Shift'],
-                    ['meta', 'Meta']
-                ];
-        }
-    }
-
     static isMetaKeySupported(os, browser) {
         return !(browser === 'firefox' || browser === 'firefox-mobile') || os === 'mac';
     }
diff --git a/ext/mixed/js/hotkey-util.js b/ext/mixed/js/hotkey-util.js
new file mode 100644
index 00000000..ea3daf97
--- /dev/null
+++ b/ext/mixed/js/hotkey-util.js
@@ -0,0 +1,297 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Utility class to help display hotkeys and convert to/from commands.
+ */
+class HotkeyUtil {
+    /**
+     * Creates a new instance.
+     */
+    constructor(os=null) {
+        this._os = os;
+        this._inputSeparator = ' + ';
+        this._modifierKeyNames = new Map();
+        this._mouseInputNamePattern = /^mouse(\d+)$/;
+        this._modifierPriorities = new Map([
+            ['meta', -4],
+            ['ctrl', -3],
+            ['alt', -2],
+            ['shift', -1]
+        ]);
+        this._stringComparer = new Intl.Collator('en-US'); // Invariant locale
+
+        this._updateModifierKeyNames();
+    }
+
+    /**
+     * Gets the operating system for this instance.
+     * The operating system is used to display system-localized modifier key names.
+     */
+    get os() {
+        return this._os;
+    }
+
+    /**
+     * Sets the operating system for this instance.
+     * @param value The value to assign.
+     *   Valid values are: win, mac, linux, openbsd, cros, android.
+     */
+    set os(value) {
+        if (this._os === value) { return; }
+        this._os = value;
+        this._updateModifierKeyNames();
+    }
+
+    /**
+     * Gets a display string for a key and a set of modifiers.
+     * @param key The key code string, or `null` for no key.
+     * @param modifiers An array of modifiers.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns A user-friendly string for the combination of key and modifiers.
+     */
+    getInputDisplayValue(key, modifiers) {
+        const separator = this._inputSeparator;
+        let displayValue = '';
+        let first = true;
+        for (const modifier of modifiers) {
+            if (first) {
+                first = false;
+            } else {
+                displayValue += separator;
+            }
+            displayValue += this.getModifierDisplayValue(modifier);
+        }
+        if (typeof key === 'string') {
+            if (!first) { displayValue += separator; }
+            displayValue += this.getKeyDisplayValue(key);
+        }
+        return displayValue;
+    }
+
+    /**
+     * Gets a display string for a single modifier.
+     * @param modifier A string representing a modifier.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns A user-friendly string for the modifier.
+     */
+    getModifierDisplayValue(modifier) {
+        const match = this._mouseInputNamePattern.exec(modifier);
+        if (match !== null) {
+            return `Mouse ${match[1]}`;
+        }
+
+        const name = this._modifierKeyNames.get(modifier);
+        return (typeof name !== 'undefined' ? name : modifier);
+    }
+
+    /**
+     * Gets a display string for a key.
+     * @param key The key code string, or `null` for no key.
+     * @returns A user-friendly string for the combination of key and modifiers, or `null` if key was already `null`.
+     */
+    getKeyDisplayValue(key) {
+        if (typeof key === 'string' && key.length === 4 && key.startsWith('Key')) {
+            key = key.substring(3);
+        }
+        return key;
+    }
+
+    /**
+     * Gets a display string for a single modifier.
+     * @param modifier A string representing a modifier.
+     *   Valid values are: ctrl, alt, shift, meta, or mouseN, where N is an integer.
+     * @returns `'mouse'` if the modifier represents a mouse button, `'key'` otherwise.
+     */
+    getModifierType(modifier) {
+        return (this._mouseInputNamePattern.test(modifier) ? 'mouse' : 'key');
+    }
+
+    /**
+     * Converts an extension command string into a standard input.
+     * @param command An extension command string.
+     * @returns An object `{key, modifiers}`, where key is a string (or `null`) representing the key, and modifiers is an array of modifier keys.
+     */
+    convertCommandToInput(command) {
+        let key = null;
+        const modifiers = new Set();
+        if (typeof command === 'string' && command.length > 0) {
+            const parts = command.split('+');
+            const ii = parts.length - 1;
+            key = this._convertCommandKeyToInputKey(parts[ii]);
+            for (let i = 0; i < ii; ++i) {
+                modifiers.add(this._convertCommandModifierToInputModifier(parts[i]));
+            }
+        }
+        return {key, modifiers: this.sortModifiers([...modifiers])};
+    }
+
+    /**
+     * Gets a command string for a specified input.
+     * @param key The key code string, or `null` for no key.
+     * @param modifiers An array of modifier keys.
+     *   Valid values are: ctrl, alt, shift, meta.
+     * @returns An extension command string representing the input.
+     */
+    convertInputToCommand(key, modifiers) {
+        const separator = '+';
+        let command = '';
+        let first = true;
+        for (const modifier of modifiers) {
+            if (first) {
+                first = false;
+            } else {
+                command += separator;
+            }
+            command += this._convertInputModifierToCommandModifier(modifier);
+        }
+        if (typeof key === 'string') {
+            if (!first) { command += separator; }
+            command += this._convertInputKeyToCommandKey(key);
+        }
+        return command;
+    }
+
+    /**
+     * Sorts an array of modifiers.
+     * @param modifiers An array of modifiers.
+     *   Valid values are: ctrl, alt, shift, meta.
+     * @returns A sorted array of modifiers. The array instance is the same as the input array.
+     */
+    sortModifiers(modifiers) {
+        const pattern = this._mouseInputNamePattern;
+        const keyPriorities = this._modifierPriorities;
+        const stringComparer = this._stringComparer;
+
+        const count = modifiers.length;
+        const modifierInfos = [];
+        for (let i = 0; i < count; ++i) {
+            const modifier = modifiers[i];
+            const match = pattern.exec(modifier);
+            let info;
+            if (match !== null) {
+                info = [modifier, 1, Number.parseInt(match[1], 10), i];
+            } else {
+                let priority = keyPriorities.get(modifier);
+                if (typeof priority === 'undefined') { priority = 0; }
+                info = [modifier, 0, priority, i];
+            }
+            modifierInfos.push(info);
+        }
+
+        modifierInfos.sort((a, b) => {
+            let i = a[1] - b[1];
+            if (i !== 0) { return i; }
+
+            i = a[2] - b[2];
+            if (i !== 0) { return i; }
+
+            i = stringComparer.compare(a[0], b[0]);
+            if (i !== 0) { return i; }
+
+            i = a[3] - b[3];
+            return i;
+        });
+
+        for (let i = 0; i < count; ++i) {
+            modifiers[i] = modifierInfos[i][0];
+        }
+
+        return modifiers;
+    }
+
+    // Private
+
+    _getModifierKeyNames(os) {
+        switch (os) {
+            case 'win':
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Windows']
+                ];
+            case 'mac':
+                return [
+                    ['alt', 'Opt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Cmd']
+                ];
+            case 'linux':
+            case 'openbsd':
+            case 'cros':
+            case 'android':
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Super']
+                ];
+            default: // 'unknown', etc
+                return [
+                    ['alt', 'Alt'],
+                    ['ctrl', 'Ctrl'],
+                    ['shift', 'Shift'],
+                    ['meta', 'Meta']
+                ];
+        }
+    }
+
+    _updateModifierKeyNames() {
+        const map = this._modifierKeyNames;
+        map.clear();
+        for (const [key, value] of this._getModifierKeyNames(this._os)) {
+            map.set(key, value);
+        }
+    }
+
+    _convertCommandKeyToInputKey(key) {
+        if (key.length === 1) {
+            key = `Key${key}`;
+        }
+        return key;
+    }
+
+    _convertCommandModifierToInputModifier(modifier) {
+        switch (modifier) {
+            case 'Ctrl': return (this._os === 'mac' ? 'meta' : 'ctrl');
+            case 'Alt': return 'alt';
+            case 'Shift': return 'shift';
+            case 'MacCtrl': return 'ctrl';
+            case 'Command': return 'meta';
+            default: return modifier;
+        }
+    }
+
+    _convertInputKeyToCommandKey(key) {
+        if (key.length === 4 && key.startsWith('Key')) {
+            key = key.substring(3);
+        }
+        return key;
+    }
+
+    _convertInputModifierToCommandModifier(modifier) {
+        switch (modifier) {
+            case 'ctrl': return (this._os === 'mac' ? 'MacCtrl' : 'Ctrl');
+            case 'alt': return 'Alt';
+            case 'shift': return 'Shift';
+            case 'meta': return 'Command';
+            default: return modifier;
+        }
+    }
+}
diff --git a/test/test-hotkey-util.js b/test/test-hotkey-util.js
new file mode 100644
index 00000000..1388c538
--- /dev/null
+++ b/test/test-hotkey-util.js
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2020-2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+const assert = require('assert');
+const {testMain} = require('../dev/util');
+const {VM} = require('../dev/vm');
+
+
+function clone(value) {
+    return JSON.parse(JSON.stringify(value));
+}
+
+function createHotkeyUtil() {
+    const vm = new VM();
+    vm.execute(['mixed/js/hotkey-util.js']);
+    const [HotkeyUtil] = vm.get(['HotkeyUtil']);
+    return new HotkeyUtil();
+}
+
+
+function testCommandConversions() {
+    const data = [
+        {os: 'win', command: 'Alt+F', expectedCommand: 'Alt+F', expectedInput: {key: 'KeyF', modifiers: ['alt']}},
+        {os: 'win', command: 'F1',    expectedCommand: 'F1',    expectedInput: {key: 'F1', modifiers: []}},
+
+        {os: 'win', command: 'Ctrl+Alt+Shift+F1',    expectedCommand: 'Ctrl+Alt+Shift+F1',    expectedInput: {key: 'F1', modifiers: ['ctrl', 'alt', 'shift']}},
+        {os: 'win', command: 'MacCtrl+Alt+Shift+F1', expectedCommand: 'Ctrl+Alt+Shift+F1',    expectedInput: {key: 'F1', modifiers: ['ctrl', 'alt', 'shift']}},
+        {os: 'win', command: 'Command+Alt+Shift+F1', expectedCommand: 'Command+Alt+Shift+F1', expectedInput: {key: 'F1', modifiers: ['meta', 'alt', 'shift']}},
+
+        {os: 'mac', command: 'Ctrl+Alt+Shift+F1',    expectedCommand: 'Command+Alt+Shift+F1', expectedInput: {key: 'F1', modifiers: ['meta', 'alt', 'shift']}},
+        {os: 'mac', command: 'MacCtrl+Alt+Shift+F1', expectedCommand: 'MacCtrl+Alt+Shift+F1', expectedInput: {key: 'F1', modifiers: ['ctrl', 'alt', 'shift']}},
+        {os: 'mac', command: 'Command+Alt+Shift+F1', expectedCommand: 'Command+Alt+Shift+F1', expectedInput: {key: 'F1', modifiers: ['meta', 'alt', 'shift']}},
+
+        {os: 'linux', command: 'Ctrl+Alt+Shift+F1',    expectedCommand: 'Ctrl+Alt+Shift+F1',    expectedInput: {key: 'F1', modifiers: ['ctrl', 'alt', 'shift']}},
+        {os: 'linux', command: 'MacCtrl+Alt+Shift+F1', expectedCommand: 'Ctrl+Alt+Shift+F1',    expectedInput: {key: 'F1', modifiers: ['ctrl', 'alt', 'shift']}},
+        {os: 'linux', command: 'Command+Alt+Shift+F1', expectedCommand: 'Command+Alt+Shift+F1', expectedInput: {key: 'F1', modifiers: ['meta', 'alt', 'shift']}}
+    ];
+
+    const hotkeyUtil = createHotkeyUtil();
+    for (const {command, os, expectedInput, expectedCommand} of data) {
+        hotkeyUtil.os = os;
+        const input = clone(hotkeyUtil.convertCommandToInput(command));
+        assert.deepStrictEqual(input, expectedInput);
+        const command2 = hotkeyUtil.convertInputToCommand(input.key, input.modifiers);
+        assert.deepStrictEqual(command2, expectedCommand);
+    }
+}
+
+function testDisplayNames() {
+    const data = [
+        {os: 'win', key: null,   modifiers: [], expected: ''},
+        {os: 'win', key: 'KeyF', modifiers: [], expected: 'F'},
+        {os: 'win', key: 'F1',   modifiers: [], expected: 'F1'},
+        {os: 'win', key: null,   modifiers: ['ctrl'], expected: 'Ctrl'},
+        {os: 'win', key: 'KeyF', modifiers: ['ctrl'], expected: 'Ctrl + F'},
+        {os: 'win', key: 'F1',   modifiers: ['ctrl'], expected: 'Ctrl + F1'},
+        {os: 'win', key: null,   modifiers: ['alt'], expected: 'Alt'},
+        {os: 'win', key: 'KeyF', modifiers: ['alt'], expected: 'Alt + F'},
+        {os: 'win', key: 'F1',   modifiers: ['alt'], expected: 'Alt + F1'},
+        {os: 'win', key: null,   modifiers: ['shift'], expected: 'Shift'},
+        {os: 'win', key: 'KeyF', modifiers: ['shift'], expected: 'Shift + F'},
+        {os: 'win', key: 'F1',   modifiers: ['shift'], expected: 'Shift + F1'},
+        {os: 'win', key: null,   modifiers: ['meta'], expected: 'Windows'},
+        {os: 'win', key: 'KeyF', modifiers: ['meta'], expected: 'Windows + F'},
+        {os: 'win', key: 'F1',   modifiers: ['meta'], expected: 'Windows + F1'},
+        {os: 'win', key: null,   modifiers: ['mouse1'], expected: 'Mouse 1'},
+        {os: 'win', key: 'KeyF', modifiers: ['mouse1'], expected: 'Mouse 1 + F'},
+        {os: 'win', key: 'F1',   modifiers: ['mouse1'], expected: 'Mouse 1 + F1'},
+
+        {os: 'mac', key: null,   modifiers: [], expected: ''},
+        {os: 'mac', key: 'KeyF', modifiers: [], expected: 'F'},
+        {os: 'mac', key: 'F1',   modifiers: [], expected: 'F1'},
+        {os: 'mac', key: null,   modifiers: ['ctrl'], expected: 'Ctrl'},
+        {os: 'mac', key: 'KeyF', modifiers: ['ctrl'], expected: 'Ctrl + F'},
+        {os: 'mac', key: 'F1',   modifiers: ['ctrl'], expected: 'Ctrl + F1'},
+        {os: 'mac', key: null,   modifiers: ['alt'], expected: 'Opt'},
+        {os: 'mac', key: 'KeyF', modifiers: ['alt'], expected: 'Opt + F'},
+        {os: 'mac', key: 'F1',   modifiers: ['alt'], expected: 'Opt + F1'},
+        {os: 'mac', key: null,   modifiers: ['shift'], expected: 'Shift'},
+        {os: 'mac', key: 'KeyF', modifiers: ['shift'], expected: 'Shift + F'},
+        {os: 'mac', key: 'F1',   modifiers: ['shift'], expected: 'Shift + F1'},
+        {os: 'mac', key: null,   modifiers: ['meta'], expected: 'Cmd'},
+        {os: 'mac', key: 'KeyF', modifiers: ['meta'], expected: 'Cmd + F'},
+        {os: 'mac', key: 'F1',   modifiers: ['meta'], expected: 'Cmd + F1'},
+        {os: 'mac', key: null,   modifiers: ['mouse1'], expected: 'Mouse 1'},
+        {os: 'mac', key: 'KeyF', modifiers: ['mouse1'], expected: 'Mouse 1 + F'},
+        {os: 'mac', key: 'F1',   modifiers: ['mouse1'], expected: 'Mouse 1 + F1'},
+
+        {os: 'linux', key: null,   modifiers: [], expected: ''},
+        {os: 'linux', key: 'KeyF', modifiers: [], expected: 'F'},
+        {os: 'linux', key: 'F1',   modifiers: [], expected: 'F1'},
+        {os: 'linux', key: null,   modifiers: ['ctrl'], expected: 'Ctrl'},
+        {os: 'linux', key: 'KeyF', modifiers: ['ctrl'], expected: 'Ctrl + F'},
+        {os: 'linux', key: 'F1',   modifiers: ['ctrl'], expected: 'Ctrl + F1'},
+        {os: 'linux', key: null,   modifiers: ['alt'], expected: 'Alt'},
+        {os: 'linux', key: 'KeyF', modifiers: ['alt'], expected: 'Alt + F'},
+        {os: 'linux', key: 'F1',   modifiers: ['alt'], expected: 'Alt + F1'},
+        {os: 'linux', key: null,   modifiers: ['shift'], expected: 'Shift'},
+        {os: 'linux', key: 'KeyF', modifiers: ['shift'], expected: 'Shift + F'},
+        {os: 'linux', key: 'F1',   modifiers: ['shift'], expected: 'Shift + F1'},
+        {os: 'linux', key: null,   modifiers: ['meta'], expected: 'Super'},
+        {os: 'linux', key: 'KeyF', modifiers: ['meta'], expected: 'Super + F'},
+        {os: 'linux', key: 'F1',   modifiers: ['meta'], expected: 'Super + F1'},
+        {os: 'linux', key: null,   modifiers: ['mouse1'], expected: 'Mouse 1'},
+        {os: 'linux', key: 'KeyF', modifiers: ['mouse1'], expected: 'Mouse 1 + F'},
+        {os: 'linux', key: 'F1',   modifiers: ['mouse1'], expected: 'Mouse 1 + F1'},
+
+        {os: 'unknown', key: null,   modifiers: [], expected: ''},
+        {os: 'unknown', key: 'KeyF', modifiers: [], expected: 'F'},
+        {os: 'unknown', key: 'F1',   modifiers: [], expected: 'F1'},
+        {os: 'unknown', key: null,   modifiers: ['ctrl'], expected: 'Ctrl'},
+        {os: 'unknown', key: 'KeyF', modifiers: ['ctrl'], expected: 'Ctrl + F'},
+        {os: 'unknown', key: 'F1',   modifiers: ['ctrl'], expected: 'Ctrl + F1'},
+        {os: 'unknown', key: null,   modifiers: ['alt'], expected: 'Alt'},
+        {os: 'unknown', key: 'KeyF', modifiers: ['alt'], expected: 'Alt + F'},
+        {os: 'unknown', key: 'F1',   modifiers: ['alt'], expected: 'Alt + F1'},
+        {os: 'unknown', key: null,   modifiers: ['shift'], expected: 'Shift'},
+        {os: 'unknown', key: 'KeyF', modifiers: ['shift'], expected: 'Shift + F'},
+        {os: 'unknown', key: 'F1',   modifiers: ['shift'], expected: 'Shift + F1'},
+        {os: 'unknown', key: null,   modifiers: ['meta'], expected: 'Meta'},
+        {os: 'unknown', key: 'KeyF', modifiers: ['meta'], expected: 'Meta + F'},
+        {os: 'unknown', key: 'F1',   modifiers: ['meta'], expected: 'Meta + F1'},
+        {os: 'unknown', key: null,   modifiers: ['mouse1'], expected: 'Mouse 1'},
+        {os: 'unknown', key: 'KeyF', modifiers: ['mouse1'], expected: 'Mouse 1 + F'},
+        {os: 'unknown', key: 'F1',   modifiers: ['mouse1'], expected: 'Mouse 1 + F1'}
+    ];
+
+    const hotkeyUtil = createHotkeyUtil();
+    for (const {os, key, modifiers, expected} of data) {
+        hotkeyUtil.os = os;
+        const displayName = hotkeyUtil.getInputDisplayValue(key, modifiers);
+        assert.deepStrictEqual(displayName, expected);
+    }
+}
+
+function testSortModifiers() {
+    const data = [
+        {modifiers: [], expected: []},
+        {modifiers: ['shift', 'alt', 'ctrl', 'mouse4', 'meta', 'mouse1', 'mouse0'], expected: ['meta', 'ctrl', 'alt', 'shift', 'mouse0', 'mouse1', 'mouse4']}
+    ];
+
+    const hotkeyUtil = createHotkeyUtil();
+    for (const {modifiers, expected} of data) {
+        const modifiers2 = hotkeyUtil.sortModifiers(modifiers);
+        assert.strictEqual(modifiers2, modifiers);
+        assert.deepStrictEqual(modifiers2, expected);
+    }
+}
+
+
+function main() {
+    testCommandConversions();
+    testDisplayNames();
+    testSortModifiers();
+}
+
+
+if (require.main === module) { testMain(main); }