JavaScript Regex Test and Replace

Question

I need to sanitize some chars. I have a solution that works but I am wondering if there is a better solution that may be faster or better or if I flat out should be approaching this differently?

function escapeStr(_str){
    if (/\"|\'|\%/g.test(_str)) {
        _str = _str.replace(/"/g, "%22");
        _str = _str.replace(/'/g, "%27");
        _str = _str.replace(/%/g, "%25");
    }
    return _str;
}

And vice versa:

function unescapeStr(_str){
    if (/\%22|\%27|\%25/g.test(_str)) {
        _str = _str.replace(/\%22/g, '"');
        _str = _str.replace(/\%27/g, "'");
        _str = _str.replace(/\%25/g, "%");
    }
    return _str;
}

Answer 1

Instead of hardcoding the characters, and their escape values specifically in your .replace call, you can pass a callback function for the replacement. I suggested that you dive into encodeURI:

So, something like:

function escapeStr(_str) {
  return _str.replace(/([%'"])/g, encodeURI)
}

function unescapeStr(_str) {
  return _str.replace(/(%(?:2[257]))/g, decodeURI)
}
const e = escapeStr, u = unescapeStr;
console.log( e("string") );
console.log( e("some\" char%s") );
console.log( u("string") );
console.log( u("some%22 char%25s") );

Answer 2

In first and second function

function escapeStr(_str){
    if (/\"|\'|\%/g.test(_str)) { // unnecessary if 
        _str = _str.replace(/"/g, "%22"); // unnecessary asigment
        _str = _str.replace(/'/g, "%27"); // unnecessary asigment
        _str = _str.replace(/%/g, "%25"); // unnecessary asigment
    }
    return _str;
}

You can add if (value) this will prevent errors while passing null of something like this

This probably more complex and optimal:

const escapeStr = str => str ? str
  .replace(/%/g, "%25")
  .replace(/"/g, "%22")
  .replace(/'/g, "%27") : str

const unescapeStr = str => str ? str
  .replace(/\%25/g, "%")  
  .replace(/\%22/g, '"')
  .replace(/\%27/g, "'") : str

And if we want to go crazy use this:

const escapeStr = str => str ? str.replace(/[%'"]/g, encodeURI) : str

const unescapeStr = str => str ? str.replace(/\(%2[257])/g, decodeURI) : str

const testData = [`"hello"`,`'world'`,`2%3`,``, `xyz`, `%22hello%22`]

for (const data of testData) {
  console.log(`${data}:`)
  console.log(`escapeStr -> ${escapeStr(data)}`)
  console.log(`escapeStr -> ${unescapeStr(data)}`)
}