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A fast and reliable flow engine for orchestration and more uses in Node.js, Deno and the browser
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Flowed Built-In resolver library

Resolvers

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Noop

Does nothing.

Useful to set tasks dependencies without executing anything.

name: flowed::Noop

params: None

results: None

Echo

Returns the input value or its transformation as the result.

Useful to apply transformations of multiple parameters into others, without executing any specific task.

name: flowed::Echo

params:

  • in: The input value.

results:

  • out: Echo of the input value. Unless transformed, it will be the same value provided in the param in.

ThrowError

Throws an error with a specified message.

Useful to stop a flow execution with a specific error, under a given condition.

name: flowed::ThrowError

params:

  • message: The message for the error to be thrown.

results: None

Conditional

Provides one of two possible results depending of a given condition.

Useful to run different parts of a flow, depending on conditions calculated for other tasks or passed as parameters.

name: flowed::Conditional

params:

  • condition: The expression to be evaluated as boolean. If truthy, the trueResult is provided, otherwise falseResult is provided.
  • trueResult: The value to be provided when condition is truthy. When this value is provided, falseResult is not.
  • falseResult: The value to be provided when condition is falsy. When this value is provided, trueResult is not.

results:

  • onTrue: The result to be provided when condition is truthy. It would have the value given in the parameter trueResult.
  • onFalse: The result to be provided when condition is falsy. It would have the value given in the parameter falseResult.

Wait

Waits for ms milliseconds and finish returning the specified result.

Useful to implement timeouts and timers.

name: flowed::Wait

params:

  • ms: Milliseconds to time out.
  • result: Value to be returned on time out.

results:

  • result: The specified value in result parameter.

SubFlow

Runs a flow using the specification and arguments provided as parameter.

Note that the context is not passed as parameter because it is shared from the outside flow.

Useful to enclose a sub-flow execution with a flow spec given as entry.

name: flowed::SubFlow

params:

  • flowSpec: Flow spec to be run as a sub-flow.
  • flowParams: Key-Value object to be used as parameters for the sub-flow.
  • flowExpectedResults: String array to specified the expected results.
  • flowResolvers: Resolvers map to run the sub-flow.

results:

  • flowResult: Key-Value object with the sub-flow execution results.

Repeater

Runs a task multiple times and finishes returning an array with all results.

If one execution fails, the resolver ends with an exception (in both parallel and not parallel modes).

Useful to repeat the same task a number of times, in a for-loop like way.

name: flowed::Repeater

params:

  • resolver: Resolver to run the task.
  • taskSpec: Task spec.
  • count: Number of times the task is going to be executed.
  • taskParams: Array of Key-Value objects with params.
  • resolverAutomapParams: Boolean to indicate if params in task are going to be auto-mapped or need explicit mapping. Defaults to false.
  • resolverAutomapResults: Boolean to indicate if resuts in task are going to be auto-mapped or need explicit mapping. Defaults to false.
  • flowId: Flow Id to be used in debugging messages.
  • parallel: Boolean to specify if the task instances can run in parallel or in sequence (waiting one to finish before starting the next one).

results:

  • results: Array of Key-Value objects with results of all executions.

ArrayMap

Runs a task multiple times taking an array of parameter groups. For each parameter group in the array, the task is run once, collecting the results in the same order in the results array. The task instances can be run in parallel or in sequence. In both cases the order in the results will be the same as the corresponding in the params parameter.

Useful to implement the Array.prototype.map() logic in a flow.

name: flowed::ArrayMap

params:

  • resolver: Resolver to run the task.
  • spec: Task spec.
  • params: Array of Key-Value objects with params.
  • automapParams: Boolean to indicate if params in task are going to be auto-mapped or need explicit mapping. Defaults to false.
  • automapResults: Boolean to indicate if resuts in task are going to be auto-mapped or need explicit mapping. Defaults to false.
  • flowId: Flow Id to be used in debugging messages.
  • parallel: Boolean to specify if the task instances can run in parallel or in sequence (waiting one to finish before starting the next one).

results:

  • results: Array of Key-Value objects with results of all executions in the corresponding order of params parameter.

Stop

Initiates the stop operation of the flow. When the returned promise is resolved, the flow has been stopped.

Useful to stop a running flow without error, under certain conditions.

name: flowed::Stop

params: None

results:

  • promise: The promise to wait for the flow to finish the stop operation.

Pause

Initiates the pause operation of the flow. When the returned promise is resolved, the flow has been paused. A paused flow can be resumed later.

Useful to pause a running flow under certain conditions.

name: flowed::Pause

params: None

results:

  • promise: The promise to wait for the flow to finish the pause operation.