plugin-api: proper IconComponent type

Co-authored-by: Juan Lulkin <jmaiz@spotify.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/plugin-api/src/icons/types.ts

@@ -15,6 +15,19 @@
  */
 
 import { ComponentType } from 'react';
-// import { SvgIconProps } from '@material-ui/core';
 
-export type IconComponent = ComponentType<any>;
+/**
+ * IconComponent is the common icon type used throughout Backstage when
+ * working with and rendering generic icons, including the app system icons.
+ *
+ * The type is based on SvgIcon from MUI, but both do not what the plugin-api
+ * package to have a dependency on MUI, nor do we want the props to be as broad
+ * as the SvgIconProps interface.
+ *
+ * If you have the need to forward additional props from SvgIconProps, you can
+ * open an issue or submit a PR to the main Backstage repo. When doing so please
+ * also describe your use-case and reasoning of the addition.
+ */
+export type IconComponent = ComponentType<{
+  fontSize?: 'default' | 'small' | 'large';
+}>;

packages/plugin-api/src/index.ts

@@ -17,6 +17,7 @@
 export * from './apis';
 export * from './app';
 export * from './extensions';
+export * from './icons';
 export * from './plugin';
 export * from './routing';
 export * from './types';