[wip] added duration example

Author: Jeff Dickey

src/commands/duration.js

@@ -0,0 +1,18 @@
+// @ flow
+
+import Command from 'cli-engine-command'
+import DurationMixin from '../mixins/duration'
+
+export default class extends DurationMixin(Command) {
+  static topic = 'cli'
+  static command = 'duration'
+  static description = 'this is an example command showing duration parsing'
+
+  static flags = [
+    {name: 'foo'}
+  ]
+
+  run () {
+    this.log(`duration: ${this.duration}`)
+  }
+}

src/index.js

@@ -4,5 +4,7 @@ export const topics = [
   {name: 'cli', description: 'example CLI engine topic'}
 ]
 
-import CLI from './commands/cli'
-export const commands = [CLI]
+export const commands = [
+  require('./commands/cli'),
+  require('./commands/duration')
+]

src/mixins/duration.js

@@ -0,0 +1,29 @@
+// @flow
+
+import Command, {type Flag} from 'cli-engine-command' // eslint-disable-line
+
+const FLAG: Flag = {
+  name: 'duration',
+  description: 'a duration',
+  required: true,
+  hasValue: true
+}
+
+declare class App extends Command {
+  duration: Date
+}
+
+export default function <T: Class<Command>> (Base: T): $Shape<Class<App>> {
+  return class DurationMixin extends Base {
+    static get flags (): Flag[] { return this._flags.concat([FLAG]) }
+    static set flags (flags: Flag[]) { this._flags = flags }
+
+    get duration (): Date {
+      this.inspect(this.constructor.flags)
+
+      // this is a little gross but I think needed to cast it to a string
+      let duration = (((this.flags.duration): any): string)
+      return new Date(duration)
+    }
+  }
+}