Overview

Workflow is a unidirectional data flow (UDF) library that provides navigation and state management for Kotlin and Swift applications. It can be compared to (and helped inspire!) TCA, Circuit and Molecule.

Workflow's main difference from its peers is its opionated take on navigation: that navigation is just another form of presenter state to be managed, not a separate special concern.

Workflow…

• Uses immutable data within each Workflow. Data flows in a single direction from source to UI, and events in a single direction from the UI to the business logic.
• Supports writing business logic and complex UI navigation logic as state machines, thereby enabling confident reasoning about state and validation of correctness.
• Provides excellent support for recursion -- workflows of workflows of workflows -- as its main idiom for navigation.
• Is optimized for composability and scalability of features and screens.
• Includes UI frameworks that bind Rendering data classes for “views” (including event callbacks) to Mobile UI frameworks for Android and iOS.
• Provides a testing framework that facilitates simple-to-write unit tests for all application business logic and helps ensure correctness.

Using Workflows in your project

Swift

See the square/workflow-swift repository.

Kotlin

See the square/workflow-kotlin repository.

Resources

• Wondering why to use Workflow? See "Why Workflow"
• There is a Glossary of Terms
• We have a User Guide describing core concepts.
• For Kotlin (and Android), there is a codelab style tutorial in the repo.
• For Swift (and iOS), there is also a Getting Started tutorial in the repo.
• There are also a number of Kotlin samples and Swift samples.

Support & Contact

Workflow discussion happens in the Workflow Community slack. Use this open invitation.

Workflow maintainers also hang out in the #squarelibraries channel on the Kotlin Slack.

Releasing and Deploying

See RELEASING.md.

License

Copyright 2019 Square Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.