var.replace is not a function

var.replace is not a function

I’m using the below code to try to trim the string in Javascript but am getting the error mentioned in the title:
function trim(str) {
return str.replace(/^\s+|\s+$/g,”);

I fixed the problem…. sorry I should have put the code on how I was calling it too…. realized I accidentally was passing the object of the form field itself rather than its value.


Solution 1:

My guess is that the code that’s calling your trim function is not actually passing a string to it.

To fix this, you can make str a string, like this: str.toString().replace(...)
…as alper pointed out below.

Solution 2:

probable issues:

  • variable is NUMBER (instead of string);

    num=35; num.replace(3,'three'); =====> ERROR

    num=35; num.toString().replace(3,'three'); =====> CORRECT !!!!!!

    num='35'; num.replace(3,'three'); =====> CORRECT !!!!!!
  • variable is object (instead of string);
  • variable is not defined;

Solution 3:

Replace wouldn’t replace numbers. It replaces strings only.

This should work.

function trim(str) {
    return str.toString().replace(/^\s+|\s+$/g,'');

If you only want to trim the string. You can simply use “str.trim()”

Solution 4:

You are not passing a string otherwise it would have a replace method. I hope you didnt type function trim(str) { return var.replace(blah); } instead of return str.replace.

Solution 5:

You should probably do some validations before you actually execute your function :

function trim(str) {
    if(typeof str !== 'string') {
        throw new Error('only string parameter supported!');

    return str.replace(/^\s+|\s+$/g,'');

Solution 6:

Did you call your function properly? Ie. is the thing you pass as as a parameter really a string?

Otherwise, I don’t see a problem with your code – the example below works as expected

function trim(str) {
    return str.replace(/^\s+|\s+$/g,'');

trim('    hello   ');  // --> 'hello'

However, if you call your functoin with something non-string, you will indeed get the error above:

trim({});  // --> TypeError: str.replace is not a function