Handling global variables in ESLint

Include code for declaring global variables in an ESLint configuration file to prevent no-undef rule from triggering.

/* .eslintrc.js (or .eslintrc.json) configuration file */
module.exports = {
  // ... other ESLint settings ...
  "globals": {
    "myGlobalVariable": "readonly" // Declare a global variable called myGlobalVariable
    // "writable" could be used if the variable should be able to be overwritten
  }
};

This is the content for the ESLint configuration file where 'myGlobalVariable' is declared. This variable can then be used within your JavaScript files without ESLint flagging it as undefined ('no-undef' rule). The value 'readonly' indicates that the variable should not be reassigned in your code, while 'writable' would allow reassignment.

// JavaScript file using the global variable
function useGlobalVar() {
  console.log(myGlobalVariable); // Access the global variable without ESLint error
}

useGlobalVar();

This is a JavaScript function that logs the value of 'myGlobalVariable' to the console. Since 'myGlobalVariable' is declared in the ESLint configuration file as a global variable, ESLint will not trigger the 'no-undef' rule when this variable is used.