Question

I’m trying to match strings that only have a, g, c or t in them (insensitive)
so the string: “AAaaatCCCc” is valid while “catb” is not.
this is my function:

var pattern = "/^[agct]+$/i";
if (!this.inputSeq.value.trim().match(pattern)){
    this.errMsg = "Invalid input sequence -must contain only a,g,c or t"
    updateErrorBox(this.errMsg);
}

When i enter valid strings i’m still getting the error message

Answer 1

Remove the quotes from the regex literal:

var pattern = "/^[agct]+$/i";

To:

var pattern = /^[agct]+$/i;

There is an implicitly conversion

regexp

A regular expression object. If a non-RegExp object obj is passed, it is implicitly converted to a RegExp by using new RegExp(obj).

MDN

But it’s not working, because you have flags in the pattern and slashes: /../.

var pattern = "^[agct]+$";
... .match(pattern)

Could work due the implicit conversion, but case sensitive because of the missing i flag.