#What is FlowEngine?

FlowEngine is a new front-end no-code/low-code development engine introduced in NocoBase 2.0. It combines Models and Flows to simplify front-end logic and improve reusability and maintainability. At the same time, it leverages the configurability of Flows to provide no-code configuration and orchestration capabilities for front-end components and business logic.

#Why is it called FlowEngine?

Because in FlowEngine, a component's properties and logic are no longer statically defined, but are driven and managed by Flows.

• Flow, like a data stream, breaks down logic into ordered steps (Steps) that are progressively applied to the component.
• Engine signifies that it is an engine that drives front-end logic and interactions.

Therefore, FlowEngine = A front-end logic engine driven by Flows.

#What is a Model?

In FlowEngine, a Model is an abstract model of a component, responsible for:

• Managing the component's properties (Props) and state.
• Defining the component's rendering method.
• Hosting and executing Flows.
• Uniformly handling event dispatching and lifecycles.

In other words, a Model is the logical brain of a component, transforming it from a static unit into a configurable and orchestratable dynamic unit.

#What is a Flow?

In FlowEngine, a Flow is a logic stream that serves a Model. Its purpose is to:

• Break down property or event logic into steps (Steps) and execute them sequentially in a stream.
• Manage property changes as well as event responses.
• Make logic dynamic, configurable, and reusable.

#How to understand these concepts?

You can think of a Flow as a stream of water:

• A Step is like a node along the water stream Each Step performs a small task (e.g., setting a property, triggering an event, calling an API), just as a stream of water has an effect when it passes through a gate or a water wheel.

• Flows are ordered A stream of water follows a predetermined path from upstream to downstream, passing through all Steps in sequence; similarly, the logic in a Flow is executed in the defined order.

• Flows can be branched and combined A stream of water can be split into multiple smaller streams or merged together; a Flow can also be broken down into multiple sub-flows or combined into more complex logical chains.

• Flows are configurable and controllable The direction and volume of a water stream can be adjusted with a sluice gate; the execution method and parameters of a Flow can also be controlled through configuration (stepParams).

Analogy Summary

• A component is like a water wheel that needs a stream of water to turn.
• A Model is the base and controller of this water wheel, responsible for receiving the water stream and driving its operation.
• A Flow is that stream of water, passing through each Step in order, driving the component to continuously change and respond.

So, in FlowEngine:

• Flows allow logic to move naturally like a stream of water.
• Models enable components to become the carriers and executors of this stream.