Uncaught syntaxerror unexpected number

Uncaught syntaxerror unexpected number

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The uncaught syntaxerror unexpected number error message typically happens while you are working with JavaScript.

If you’re wondering and perplexed why it occurs and how to troubleshoot this error message, keep reading.

This article will discuss the solutions to fix the uncaught syntaxerror: unexpected number error message.

What is “uncaught syntaxerror: unexpected number”?

The error message uncaught syntaxerror unexpected number occurs when there is an issue with the syntax of your code.

For instance, it could be caused by a space between a variable name and a number or by leading zeros in an array of numbers.

Here’s an example code that results in this error:

let a = 10;
let b = a 15;
console.log(b);

Output:

index.js:2
let b = a 15;
          ^^

SyntaxError: Unexpected number

This error message indicates that the JavaScript engine has encountered a number where it did not expect one.

Why does the “uncaught syntaxerror unexpected number” error occur?

The unexpected number, an uncaught syntaxerror occurs when the JavaScript engine encounters a number where it did not expect one.

And this error occurs due to several factors that, include the following:

  1. Missing operator between two numbers

If you are working with numerical values in JavaScript, it is important to include an operator between two numbers to perform arithmetic operations.

For example:

let sample = 50 70;

To fix this issue, you can include a suitable operator such as (+, -, *, or /) between the two numbers causing the error.

Adding an operator will ensure that the numbers are used in a valid expression, and it resolves the error.

Here’s the corrected code:

let sample = 50 + 70;
console.log(sample);

Output:

120

  1. Invalid decimal number format

In JavaScript, when declaring decimal numbers, it is important to adhere to a specific format. You must use a period (.) as the decimal separator.

Using a comma (,) or any other character can raise uncaught syntaxerror: unexpected number error.

For example:

let amount= 10,99;

To resolve this error, replace the comma with a period:

let amount= 10.99;

  1. Misplaced or missing parentheses

Parentheses are essential for grouping expressions and controlling the order of operations in programming.

They help clarify the desired precedence and ensure that calculations are performed correctly.

By using parentheses effectively, you can avoid ambiguity and ensure that your code executes as intended.

For example:

let sample = 100 * 10 /5 );

In this case, the opening parenthesis “)” is missing. To correct this error, you need to place the parenthesis in the correct location in the expression.

Here’s the corrected code:

let total = 100 * (10 / 5 );
console.log(total);

Output:

200

How to fix “uncaught syntaxerror unexpected number”?

To fix the uncaught syntaxerror: unexpected number error, you need to identify the part of your code that is causing the error and correct the syntax.

This error usually occurs when there is an issue with the syntax of the code, such as a space between a variable name and a number or leading zeros in an array of numbers.

Here are some steps you can follow to fix this error:

Solution 1: Remove the space between a variable name and a number

Check your code for any spaces between variable names and numbers.

If you find any, either remove the space to concatenate the variable and the number into a string or add an operator between them to perform a mathematical operation.

For example:

let a = 10;
let b = a + '15';✅

console.log(b);

As you have noticed, we concatenate the variable and the number into a string.

Output:

1015

Solution 2: Add an operator between a variable name and a number

When there is a space between a variable name and a number in your code, you can also fix the error by adding an operator between them to perform a mathematical operation.

For example:

let a = 10;
let b = a + 15;✅

console.log(b);

Output:

25

Solution 3: Remove leading zeros from numbers in an array

Check your code for any arrays of numbers with leading zeros. If you find any, remove the leading zeros from the numbers.

You can fix the error by removing the leading zeros from the numbers.

Incorrect code:

let sampleArray = [01, 02, 03, 04, 05, 06, 07, 08, 09]

Corrected code:

let sampleArray = [1, 2, 3, 4, 5, 6, 7, 8, 9];✅

console.log(sampleArray);

Output:

[
  1, 2, 3, 4, 5,
  6, 7, 8, 9
]

or

let sampleArray = [10, 20, 30, 40, 50, 60, 70, 80, 90, 100];✅

console.log(sampleArray);

Output:

[
  10, 20, 30, 40, 50,
  60, 70, 80, 90, 100
]

Solution 4: Use string values instead of numbers with leading zeros

If you need to use values with leading zeros in your code (for example, for display purposes), you can fix the error by using string values instead of numbers.

let sampleArray = ['01', '02', '03', '04', '05', '06', '07', '08', '09']; ✅

console.log(sampleArray);

Output:

[
  '01', '02', '03',
  '04', '05', '06',
  '07', '08', '09'
]

Conclusion

In conclusion, the error message uncaught syntaxerror unexpected number occurs when there is an issue with the syntax of your code. For instance, it could be caused by a space between a variable name and a number or by leading zeros in an array of numbers.

To fix this error, you need to identify the part of your code that is causing the error and correct the syntax.

This article already discussed what this error is all about and multiple ways to resolve this error.

By executing the solutions above, you can master this SyntaxError with the help of this guide.

You could also check out other SyntaxError articles that may help you in the future if you encounter them.

We are hoping that this article helps you fix the error. Thank you for reading itsourcecoders 😊

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