From 9b99d8bf876e3cc863714d0b2135e6918648feb6 Mon Sep 17 00:00:00 2001
From: Mark Sujew <mark.sujew@typefox.io>
Date: Tue, 31 Aug 2021 14:15:29 +0000
Subject: [PATCH] Replace `instanceof ThemeIcon` with an `is` method

---
 packages/plugin-ext/src/plugin/quick-open.ts      | 4 ++--
 packages/plugin-ext/src/plugin/tree/tree-views.ts | 2 +-
 packages/plugin-ext/src/plugin/types-impl.ts      | 6 ++++++
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/packages/plugin-ext/src/plugin/quick-open.ts b/packages/plugin-ext/src/plugin/quick-open.ts
index 3e339e447e629..8a91373630d6e 100644
--- a/packages/plugin-ext/src/plugin/quick-open.ts
+++ b/packages/plugin-ext/src/plugin/quick-open.ts
@@ -41,7 +41,7 @@ export function isPromiseCanceledError(error: any): boolean {
 }
 
 export function getIconUris(iconPath: theia.QuickInputButton['iconPath']): { dark: URI, light: URI } | { id: string } {
-    if (iconPath instanceof ThemeIcon) {
+    if (ThemeIcon.is(iconPath)) {
         return { id: iconPath.id };
     }
     const dark = getDarkIconUri(iconPath as URI | { light: URI; dark: URI; });
@@ -439,7 +439,7 @@ export class QuickInputExt implements QuickInput {
             const relativePath = path.relative(packagePath, normalizedPath);
             return PluginPackage.toPluginUrl(this.plugin.rawModel, relativePath);
         };
-        if ('id' in iconPath || iconPath instanceof ThemeIcon) {
+        if (ThemeIcon.is(iconPath)) {
             return iconPath;
         } else if (typeof iconPath === 'string' || iconPath instanceof monaco.Uri) {
             return URI.parse(toUrl(iconPath));
diff --git a/packages/plugin-ext/src/plugin/tree/tree-views.ts b/packages/plugin-ext/src/plugin/tree/tree-views.ts
index 0009270d34340..6d7957d2fd3e4 100644
--- a/packages/plugin-ext/src/plugin/tree/tree-views.ts
+++ b/packages/plugin-ext/src/plugin/tree/tree-views.ts
@@ -369,7 +369,7 @@ class TreeViewExtImpl<T> implements Disposable {
                 const { iconPath } = treeItem;
                 if (typeof iconPath === 'string' && iconPath.indexOf('fa-') !== -1) {
                     icon = iconPath;
-                } else if (iconPath instanceof ThemeIcon) {
+                } else if (ThemeIcon.is(iconPath)) {
                     themeIconId = iconPath.id;
                 } else {
                     iconUrl = PluginIconPath.toUrl(<PluginIconPath | undefined>iconPath, this.plugin);
diff --git a/packages/plugin-ext/src/plugin/types-impl.ts b/packages/plugin-ext/src/plugin/types-impl.ts
index 8b99e33f181b3..f15792f7ae1d7 100644
--- a/packages/plugin-ext/src/plugin/types-impl.ts
+++ b/packages/plugin-ext/src/plugin/types-impl.ts
@@ -702,6 +702,12 @@ export class ThemeIcon {
 
 }
 
+export namespace ThemeIcon {
+    export function is(item: unknown): item is ThemeIcon {
+        return typeof item === 'object' && !!item && 'id' in item;
+    }
+}
+
 export enum TextEditorRevealType {
     Default = 0,
     InCenter = 1,