Скачать или смотреть How to fix "SyntaxError: Missing formal parameter"

SyntaxError missing before formal parameters
The "SyntaxError: Missing formal parameter" error occurs in JavaScript when you try to define a function without providing the required parameters or arguments. To fix this error, you need to ensure that you provide the correct number of parameters when defining and calling your functions. Here's how to address this issue:

Check Function Definition:
Review the function definition where the error occurs. Make sure you have correctly specified the parameters that the function expects.

Add Required Parameters:
If you are missing parameters in the function definition, add them in the correct order. Each parameter should be separated by a comma.

javascript

function myFunction(parameter1, parameter2) {
// Function code here
}

Pass Arguments when Calling:
When calling the function, ensure that you provide the required arguments. The number of arguments passed should match the number of parameters defined in the function.

javascript

myFunction(value1, value2);

Check Function Calls:
Review all places where the function is called to ensure that the correct number of arguments is passed.

Use Default Parameters (ES6+):
If your JavaScript environment supports ES6 (ECMAScript 2015) or newer, you can use default parameters to provide default values for parameters that may be missing.

javascript

function myFunction(parameter1 = defaultValue1, parameter2 = defaultValue2) {
// Function code here
}

Check Syntax and Typos:
Ensure that there are no syntax errors or typos in your function definitions and calls. Even a small mistake can lead to this error.

Test and Debug:
After making the necessary changes, test your code to ensure that the "SyntaxError: Missing formal parameter" error is resolved and that your functions work as expected.

Here's an example of a corrected function definition and call:

javascript

// Corrected function definition with parameters
function greet(name) {
console.log("Hello, " + name + "!");
}

// Call the function with an argument
greet("Alice");

By ensuring that you provide the correct number of parameters and arguments in your function definitions and calls, you can fix the "SyntaxError: Missing formal parameter" error in your JavaScript code.