trigger_automatic_stripe_payment.js

function log(msg) {
  nlapiLogExecution('DEBUG', msg);
}

function startsWith(str, searchString) {
  return str.indexOf(searchString) === 0;
}

function isEmpty(obj) {
  return obj === undefined || obj === null || obj === "";
}

function triggerStripePayment(invoiceInternalID) {
  var invoiceCustomerID = nlapiLookupField('invoice', invoiceInternalID, 'entity')
  var stripeCustomerID = nlapiLookupField('customer', invoiceCustomerID, 'externalid');

  if(isEmpty(stripeCustomerID)) {
    log("no external ID detected, no Stripe customer exists");
    return null;
  }

  if(startsWith(stripeCustomerID, 'cus_')) {
    nlapiSubmitField('invoice', invoiceInternalID, 'custbody_suitesync_authorization_code', stripeCustomerID);
  } else {
    log("external ID does not look like a Stripe customer ID: " + stripeCustomerID)
  }
}

if(nlapiGetContext().getExecutionContext() == 'debugger') {
  triggerStripePayment(14441564);
}

// allows you set a breakpoint at the end of the script
'debug';