Javascript Import Variables

by

Summary

The issue at hand is related to JavaScript modules and the use of import/export statements. The goal is to maintain all JavaScript Regular Expressions in a separate file for easier management. However, the developer is encountering errors when trying to use import/export statements.

Root Cause

The root cause of the issue is due to the following reasons:

  • The export statement is not supported in non-module scripts.
  • The import statement cannot be used outside a module.
  • The path to the module file is not specified correctly.

Why This Happens in Real Systems

This issue occurs in real systems when developers try to use ES6 modules in a browser environment without proper configuration. The import/export statements are not supported in older browsers or when the script is not marked as a module.

Real-World Impact

The impact of this issue is:

  • Error messages: Uncaught SyntaxError: Unexpected token ‘export’ and Uncaught SyntaxError: Cannot use import statement outside a module.
  • Code not executing: The JavaScript code will not execute as expected, leading to functional issues.
  • Maintenance difficulties: Without a proper module system, maintaining and updating code can become challenging.

Example or Code

// 99_JS_regex.js
export const JS_Email_RG = "/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/";
// 01_JScript_Main.js
import { JS_Email_RG } from './99_JS_regex.js';

$(document).ready(function(){
  $("#Login_Button").click(function(){
    alert(JS_Email_RG);
  });
});

How Senior Engineers Fix It

Senior engineers fix this issue by:

  • Marking the script as a module using the type="module" attribute.
  • Using the correct path to the module file.
  • Ensuring that the import/export statements are used correctly.
  • Configuring the browser to support ES6 modules.

Why Juniors Miss It

Juniors may miss this issue due to:

  • Lack of understanding of JavaScript modules and import/export statements.
  • Insufficient knowledge of browser support for ES6 modules.
  • Incorrect usage of path to the module file.
  • Not marking the script as a module.