TypeError: toFixed is not a function in JavaScript

You might have come across a use case where you need to format a number to fixed decimal places. For example, you might want to format a number to 2 decimal places. You can use the toFixed() method to do this.

1const num = 123.456
2const formattedNum = num.toFixed(2)
3console.log(formattedNum) // 123.46

However, sometimes you might get the following error while using the toFixed() method.

1Uncaught TypeError: "num".toFixed is not a function

You will get this error because the toFixed() method is only available for numbers. If you try to use it on a string, you will get the above error.

1const num = "123.456"
2const formattedNum = num.toFixed(2)
3console.log(formattedNum) // Uncaught TypeError: "num".toFixed is not a function

To fix this error, you have to convert the string to a number. You can use the Number() method to convert a string to a number.

1const num = "123.456"
2const formattedNum = Number(num).toFixed(2)
3console.log(formattedNum) // 123.46

If you are still getting the error, then you have to check if the variable is a number or not. You can use the isNaN function to check if the variable is a number or not.

1const numStr = "123.456"
2const num = Number(numStr)
3if (!isNaN(num)) {
4  const formattedNum = num.toFixed(2)
5  console.log(formattedNum)
6} else {
7  console.log("The variable is not a number")
8}

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