feat: add InferredFlags type

src/interfaces/flags.ts

@@ -0,0 +1,33 @@
+import {FlagInput} from './parser'
+
+/**
+ * Infer the flags that are returned by Command.parse. This is useful for when you want to assign the flags as a class property.
+ *
+ * @example
+ * export type StatusFlags = Interfaces.InferredFlags<typeof Status.flags & typeof Status.globalFlags>
+ *
+ * export abstract class BaseCommand extends Command {
+ *   static enableJsonFlag = true
+ *
+ *   static globalFlags = {
+ *     config: Flags.string({
+ *       description: 'specify config file',
+ *     }),
+ *   }
+ * }
+ *
+ * export default class Status extends BaseCommand {
+ *   static flags = {
+ *     force: Flags.boolean({char: 'f', description: 'a flag'}),
+ *   }
+ *
+ *   public flags!: StatusFlags
+ *
+ *   public async run(): Promise<StatusFlags> {
+ *     const result = await this.parse(Status)
+ *     this.flags = result.flags
+ *     return result.flags
+ *   }
+ * }
+ */
+export type InferredFlags<T> = T extends FlagInput<infer F> ? F & { json: boolean | undefined; } : unknown

src/interfaces/index.ts

@@ -19,3 +19,4 @@ export {PJSON} from './pjson'
 export {Plugin, PluginOptions, Options} from './plugin'
 export {Topic} from './topic'
 export {TSConfig} from './ts-config'
+export {InferredFlags} from './flags'