Solution To Fix “SyntaxError: Unexpected token” Error in JavaScript

To fix SyntaxError: Unexpected token in JavaScript, we must first understand the reason for the error and then figure out how to fix it correctly. This is a fairly common error for newbies and rarely appears for veterans, but fortunately, fixing it is very simple.

Why is SyntaxError: Unexpected token in JavaScript happening?

The error SyntaxError: Unexpected token in JavaScript can be a basic typo, appearing when a statement is syntactically incorrect. Once or more characters we type in excess or missing will lead to the above error.

The error message occurs as follows:

Uncaught SyntaxError: Unexpected token

In this tutorial, I will show you how to fix this error in two cases: incorrect use of JSON.loads() and empty JSON file.

How to fix this error?

Let’s follow two steps below to fix this error.

Step 1: Find out the cause of the error

Since this error is a typo, the first step is to check where the error is and how it is, and then provide a solution.

Example 1:

var num = [1,2,4,5,7,9];
var sum = 0 ;

for(let i = 0 ; i < num.length ,; i++ )
    sum = sum + num[i];

console.log(sum);

Output: 

Uncaught SyntaxError: Unexpected token ';' (at main.js:3:33)

In this example, my error is in line 3, position 33 in the line from the left. When I look at it, I see that I put an extra  ” , ” and the program generates an error, so the error is because I marked it too much ” , “.

Example 2:

var currentDate = new Date();
var firstDayOfMonth = new Date(currentDate.getFullYear(), currentDate.getMonth, 1);
var lastDayOfMonth = new Date(currentDate.getFullYear(), currentDate.getMonth + 1 , 0);

if(currentDate.getDate == lastDayOfMonth.getDate())||(currentDate.getDate() == 1)
    console.log("This is the first or last day of the month");

else
    console.log("This is not the first or last day of the month");

Output:

Uncaught SyntaxError: Unexpected token '||' (at main.js:5:52)

This example shows my error in line 5, position 52 in the line from the left. After checking, I find two characters, “()” are missing to close the if condition.

Step 2: Fix error

Once we find out what caused the error, we can start fixing it.

In example 1, we see the error because I have marked an extra  ” , ” so the program generates an error. To fix this error, I will do the following:

var num = [1,2,4,5,7,9];
var sum = 0 ;

for(let i = 0 ; i < num.length ; i++ )
    sum = sum + num[i];

console.log(sum);

Output: 

28

The code seems to have not changed, but the program usually runs. That’s because I removed the error-generating agent and the  ” , ” that I added. Then the program will no longer have errors and will run normally.

In example 2, we see the error because I was missing two “()” signs, so the program generates an error. To fix this error, I will do the following:

var currentDate = new Date();
var firstDayOfMonth = new Date(currentDate.getFullYear(), currentDate.getMonth, 1);
var lastDayOfMonth = new Date(currentDate.getFullYear(), currentDate.getMonth + 1 , 0);

if((currentDate.getDate == lastDayOfMonth.getDate())||(currentDate.getDate() == 1))
    console.log("This is the first or last day of the month");

else
    console.log("This is not the first or last day of the month");

Output:

This is not the first or last day of the month

My program usually runs after I add the two “()” s that I missed.

Summary

SyntaxError: Unexpected token in JavaScript is a fundamental error, but to avoid reencountering it while writing the code, you should pay more attention to not redundant or redundant characters. I hope this article will help you fix the error in your program, so you won’t have to face the same problem again. Good luck.