Compute and declare a field

The workflow adds the field discount amount to incoming invoices, and its script computes it: 2 % of the gross total, rounded to the cent. This is how a coded workflow adds a field your document types don’t have yet, and fills it at once.

The workflow

The workflow starts for every document of the type incoming-invoice. Its file workflow.yaml:

$schema: 'https://docs.acriva.de/schemas/workflow.schema.json'
format: 1
schemaVersion: 4
sdk: '1.0.0'
key: computed-field
name: Feld berechnen und deklarieren
template: custom
trigger:
  documentType: incoming-invoice
fields:
  - key: discountAmount
    kind: money
    labelDe: Skontobetrag
    labelEn: Discount amount
    documentTypes:
      - incoming-invoice
start: compute
steps:
  - kind: script
    name: compute
    label: Skontobetrag berechnen
    script: compute.ts
    hook: onDocumentArrived
    inputs:
      - kind: field
        key: totalGross
        type: money
    returns: []
    exits: []
    next: approve
  - kind: humanTask
    name: approve
    label: Freigabe
    taskKind: approve
    assignees:
      - when: null
        assignee:
          kind: costCenterResponsible
    fallback:
      kind: role
      role: Buchhaltung
    options:
      excludeRequester: true
      excludeActorsOfSteps: []
      pickFile: false
    next: approved
    onRejected: rejected
  - kind: end
    name: approved
    label: Freigegeben
    outcome: approved
  - kind: end
    name: rejected
    label: Zurückgewiesen
    outcome: rejected

The script compute.ts

Hook: onDocumentArrived · Inputs: totalGross · Return values: none

import { defineScript, money } from '@acriva/workflow-sdk';

/** The early-payment discount, as a share of the gross total. */
const DISCOUNT_RATE = 0.02;

export default defineScript({
  hook: 'onDocumentArrived',
  run(ctx) {
    const total = ctx.document.fields.totalGross;
    // Without a gross total there is nothing to compute, and the field stays empty.
    if (total == null) return;
    // money.round rounds half away from zero to cents: 1.995 becomes 2.00.
    const discount = money.round(total * DISCOUNT_RATE);
    ctx.log('Discount', money.format(discount));
    ctx.setField('discountAmount', discount);
  },
});

What it does

A test runs each of these cases in the sandbox and compares the result.

An invoice of €1,249.50

• Input: totalGross 1249.5
• Exit: the default next step
• Changes: field discountAmount = 24.99

An invoice without a gross total

• Input: totalGross null
• Exit: the default next step
• Changes: none

An amount that rounds up

• Input: totalGross 99.75
• Exit: the default next step
• Changes: field discountAmount = 2