Question

A continuation of my previous question…

After testing the text format, if it is not the correct format I would like to figure out which pairs of hex values are incorrect (i.e. any pair that contains value(s) other than[0-9A-Fa-f]).

if( validFormat ) {
// do processing
}
else {
// find invalid hex value pairs
}

What is the most efficient way to obtain a list of incorrect(invalid) hex pairs so that I can report back the errors and their associated hex pairs.

Edit for additional question

Also, how would I go about testing to ensure there is not a “double space” anywhere, because that also constitutes for invalid format even though the hex pairs may be valid.

Thanks!

Answer 1

The easiest is to find all values and scan for those that are not valid:

var isHexPair = /^[0-9a-f]{2}$/i;
var allPairs = myTextArea.value.split(/\s+/);
var notHex   = [];
for (var i=allPairs.length;i--;){
  if (!isHexPair.test(allPairs[i])){
    notHex.push(allPairs(i));
  }
}

That regex says:

• ^ starting at the beginning of the string
• [0-9a-f] find any character that is a digit or a-f
• {2} find exactly two of them
• $ making sure that we are now at the end of the string
• i and make it case-insensitive (allow A-F as well as a-f)

With the above you can then do:

if (notHex.length){
  // There is at least one invalid entry
}else{
  // all is well
}

---

Edit: If you explicitly want to test that the string contains nothing but single-byte hex strings separated by a single space, the simplest test would just be:

if (/^([0-9a-f]{2} )+[0-9a-f]{2}$/i.test(myStr)){ /* valid! */ }