Flutter Flow - Custom Action Not working on Android APK

I am new to flutter flow & Dart, while using custom action which I linked to my widget in action flow editor everything went smoothly until I found an abnormal behavior ( There are no visible errors in my program ):

On Debug mode action is working perfectly.
On run mode action is working on windows but in flutter flow viewer app for android that particular page is not even opening up.
In apk-release file page is opening but after I enter all my values and press button action is not performed, or should I say nothing happens.

This is the code/Custom Action I'm using in flutter flow :-

import 'dart:convert';

// This is only for clarification of arguments passed...
void main(){
  foreSupportCalc(
  12, //from textinput
  45, //from textinput
  "20 guage", //from dropdown
  5, //from counter
  6, //from textinput
  "14 guage", //from dropdown
  1, //from counter
  350, //from AppState
  1500, //from ApSate
  '{"14": 2, "16": 1.5, "20": 1}', //from ApSate
  '{"14": 175, "16": 150, "18": 130}'); //from AppState
}

// Main Custom Action starts here
Future<String> foreSupportCalc(
  double shelfWidth,
  double shelfLength,
  String shelfGuage,
  int shelfQuantity,
  double angleHeight,
  String angleGuage,
  int rackQuantity,
  double metalRates,
  double labourRates,
  String shelfGuageMap,
  String angleGuageMap,
) async {
  if (shelfWidth != null &&
      shelfLength != null &&
      shelfGuage != null &&
      shelfQuantity != null &&
      angleHeight != null &&
      angleGuage != null &&
      rackQuantity != null) {
    shelfWidth += 3;
    shelfLength += 3;
    Map<String, dynamic> shelfGuages = json.decode(shelfGuageMap);
    Map<String, dynamic> angleGuages = json.decode(angleGuageMap);
    double shelfGuage_mm = shelfGuages[shelfGuage.replaceAll(" guage", "")];
    double angleGuage_rate = angleGuages[angleGuage.replaceAll(" guage", "")];

    // Shelf Rates
    double perShelfRate = (((shelfWidth * shelfLength) / 144) *
            shelfGuage_mm * metalRates)
        .roundToDouble();
    double totalShelfRate = perShelfRate * shelfQuantity;
    double totalShelfRateForMultiRack = totalShelfRate * rackQuantity;
    int multiShelfQty = shelfQuantity * rackQuantity;
    // Angle Rates
    double perAngleRate = (angleGuage_rate * angleHeight).roundToDouble();
    double totalAngleRate = perAngleRate * 4;
    double totalAngleRateForMultiRack = totalAngleRate * rackQuantity;
    int multiAngleQty = 4 * rackQuantity;
    // Total Rack Cost
    double perRackCost = totalShelfRate + totalAngleRate + labourRates;
    double totalRackCost = perRackCost * rackQuantity;
    // Labour Rates
    double multiLabourRates = labourRates * rackQuantity;
    // Rates as String
    Map<String, dynamic> outputAns;
    if (rackQuantity > 1) {
      outputAns = {
        'Per Shelf Rates': perShelfRate,
        'Per Angle Rates': perAngleRate,
        '_+': '-:-',
        'Shelf Rates ($multiShelfQty)': totalShelfRateForMultiRack,
        'Angle Rates ($multiAngleQty)': totalAngleRateForMultiRack,
        'Labour, etc Cost': multiLabourRates,
        '__+': '-:-',
        'Rates Per Rack': perRackCost,
        'Rate for $rackQuantity Racks': totalRackCost
      };
    } else {
      outputAns = {
        'Per Shelf Rates': perShelfRate,
        'Per Angle Rates': perAngleRate,
        '-': '-',
        'Shelf Rates ($shelfQuantity)': totalShelfRate,
        'Angle Rates (4)': totalAngleRate,
        'Labour, etc Cost': labourRates,
        '-:': '-',
        'Rates Per Rack': perRackCost,
      };
    }

    String result = '';
    // Iterate over map entries
    outputAns.forEach((key, value) {
      // Concatenate each key-value pair into the string
      result += '$key: $value\n';
    });
    result = result.replaceAll("_+:", "");
    result = result.replaceAll("__+:", "");
    return result;
  } else {
    return "Error: Something is missing!";
  }
}

This should be the output of this action which I'm passing in an alert dialog box :-

Per Shelf Rates: Rs.1750
Per Angle Rates: Rs.1050
-:-
Shelf Rates (5): Rs.8750
Angle Rates (4): Rs.4200
Labour, etc Cost: Rs.1500
-:-
Rates Per Rack: Rs.14450

I tried to manipulate the code and also use simpler test code like just returning a sample String which in that case worked fine on all platforms, but this code isn't. i also double checked the data types of my AppState variables and those were ok.

If its working in Debug, then why not in android?

EDIT: After using web log Ctrl+Shift+j saw this on my console:

Uncaught TypeError: J.bV(...).aj is not a function
    at Object.eO (main.dart.js:29145:24)
    at Object.ayg (main.dart.js:5764:3)
    at aN2.$1 (main.dart.js:88145:19)
    at bEg (main.dart.js:4101:17)
    at main.dart.js:4109:51

Solution

Answer ( For future, if anyone encounters same problem )

Thankyou everyone for not responding to my request, however I found the the problem causing this error which was in this line of code:

String shelfGuageMap = '{"14": 2, "16": 1.5, "20": 1}';
String angleGuageMap = '{"14": 175, "16": 150, "18": 130}';
Map<String, dynamic> shelfGuages = json.decode(shelfGuageMap);
Map<String, dynamic> angleGuages = json.decode(angleGuageMap);

Seems like flutter flow does not support String to Map conversion on android or at least not in my case, So I changed the whole logic to:

String shelfGuageList = '["11:3", "12:2.5", "13:2.5", "14:2"]';
String angleGuageList = '["11:140", "12:150", "13:160", "14:175"]';
List<String> shelfGuageToList = json.decode(shelfGuageList).cast<String>();
List<String> angleGuageToList = json.decode(angleGuageList).cast<String>();

Now, don't know why this was an issue but Code is finally working on all devices.