create onboarding model

src/state/models/discovery/onboarding.ts

@@ -0,0 +1,63 @@
+import {makeAutoObservable} from 'mobx'
+import {RootStoreModel} from '../root-store'
+import {NavigationProp} from 'lib/routes/types'
+import {hasProp} from 'lib/type-guards'
+
+enum OnboardingStep {
+  WELCOME = 'WELCOME',
+  BROWSE_FEEDS = 'BROWSE_FEEDS',
+  COMPLETE = 'COMPLETE',
+}
+
+export class OnboardingModel {
+  // state
+  step: OnboardingStep
+
+  constructor(public rootStore: RootStoreModel) {
+    makeAutoObservable(this, {rootStore: false})
+    this.step = OnboardingStep.WELCOME
+  }
+
+  serialize() {
+    return {
+      step: this.step,
+    }
+  }
+
+  hydrate(v: unknown) {
+    if (typeof v === 'object' && v !== null) {
+      if (hasProp(v, 'step') && typeof v.step === 'string') {
+        this.step = v.step as OnboardingStep
+      }
+    }
+  }
+
+  nextStep(navigation?: NavigationProp) {
+    switch (this.step) {
+      case OnboardingStep.WELCOME:
+        this.step = OnboardingStep.COMPLETE
+        break
+      case OnboardingStep.BROWSE_FEEDS:
+        this.step = OnboardingStep.COMPLETE
+        break
+      case OnboardingStep.COMPLETE:
+        if (!navigation) {
+          throw new Error('Navigation prop required to complete onboarding')
+        }
+        this.complete(navigation)
+        break
+    }
+  }
+
+  complete(navigation: NavigationProp) {
+    navigation.navigate('Home')
+  }
+
+  reset() {
+    this.step = OnboardingStep.WELCOME
+  }
+
+  get isComplete() {
+    return this.step === OnboardingStep.COMPLETE
+  }
+}