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Tree Traversal in Workflow Definition

Your workflow is represented as a tree structure according to the specific definition. There can be multiple motivations for navigating through this tree. It is important to be aware that performing this operation requires a significant amount of processing power, so it is advisable to undertake it only when absolutely necessary. Additionally, it is recommended to utilize a cache to store the outcomes of the traversal.

if
|___ true
    |___ someTask
|___ false
    |___ someOtherTask

Get Parents​

To retrieve the ancestors of a particular step, you can invoke the getStepParents() method of the Designer class.

Designer.getStepParents(needle: Sequence | Step | string): (Step | string)[];

This function can accept either a step, a step id or a sequence as its input. Its result is an array that includes all the parent steps and the parent branch names, arranged in a top-to-bottom sequence. The final element in the array corresponds to the step provided as input.

const designer = Designer.create(/* ... */);

const step: Step = /* ... */;
const result: (Step | string)[] = designer.getStepParents(step);
// result[0] = { componentType: 'switch', type: 'if', ... }
// result[1] = 'true'
// result[2] = step

By applying a filtering mechanism to the resulting array, you have the ability to conveniently exclude branch names if needed.

const parents: Step[] = result.filter((item) => typeof item === 'object');

React, Angular and Back-end​

To get parents of a step in React, Angular or back-end, you need to use the DefinitionWalker class from the sequential-workflow-model package.

import { DefinitionWalker } from 'sequential-workflow-model';
const walker = new DefinitionWalker();

Now you need to call the getParents() method. This method expects two arguments.

DefinitionWalker.getParents(definition: Definition, needle: Sequence | Step | string): (Step | string)[];

The first one is the current definition, the second is a step, a step id or a sequence that you want to get parents of.

walker.getParents(definition, step);

For Each​

It's possible to iterate through all the steps in a definition by using the forEach() method of the DefinitionWalker class.

import { DefinitionWalker } from 'sequential-workflow-model';
const walker = new DefinitionWalker();

walker.forEach(definition, (step: Step, index: number, parentSequence: Sequence) => {
  if (check(step)) {
    return false; // stop iteration
  }
  // ...
});

The method accepts two arguments - the definition and a callback function. The callback function is invoked for each step in the definition. When the callback function returns false, the iteration is stopped.