node step module example without error throwing to avoid any troubles related to it

step-without-error-thrown.js

var Step = require("step");

function genRandomError() {
  let i = Math.floor(Math.random() * 2) + 1;
  if (i === 1) {
    return Error("Error occured!");
  }
  return "Success";
}

// Step without throwing error.
// This comes up with using each function's `result` the 2nd arg
//  as Error Object on case that error occured. 
Step(
  // Step1:
  function() {
    console.log("step1:");
    return genRandomError();
  },
  // Step2:
  function(err, result) {
    console.log("step2:");
    console.log(" err=", err);
    if (result instanceof Error) return result;
    return result;
  },
  // Step3:
  function(err, result) {
    console.log("step3:");
    if (result instanceof Error) {
      return console.error("result=", result);
    }
    return console.log(" err=", err, ", result=", result);
  });

/* 
### Result:

step1:
step2:
 err= undefined
step3:
 err= undefined , result= Success

or

step1:
step2:
 err= undefined
step3:
result= Error: Error occured!
    at Error (native)
    at genRandomError
*/