Question

I am replacing words in a string and I’m trying to match based on '\b' + myword + '\b'
However this does not work when myword has a non word character on either end.

var myword1 = "testword,";
var myword2 = "(testword";
var testString = "<tag>asdftestword, is a (testwordasdf also (testword </tag> (testword, should be replaced everywhere there is a testword,)";

var rx1 = new RegExp(???(myword1) ,'g');
var rx2 = new RegExp(???(myword2) ,'g');
var result1 = testString.replace(rx1, "replacement");
var result2 = testString.replace(rx2, "replacement");

I would like the results to be

result1 == "<tag>asdftestword, is a (testwordasdf also (testword </tag> (replacement should be replaced everywhere there is a replacement)"
result2 == "<tag>asdftestword, is a (testwordasdf also replacement </tag> replacement, should be replaced everywhere there is a testword,)"

Answer 1

Ok, I’ve finally figured this out. It looks like it is too complex to do with just a single RegExp I need multiple!

See it in action Here

function EscapeRegex(text) {
    if (!RegExp.sRE) {
    var chars = '/.*+?|()[]{}\\'.split('');
    RegExp.sRE = new RegExp('\\'+chars.join('|\\'), 'g');
    }
    return text.replace(RegExp.sRE, '\\$&');
}

function ReplaceWholeWord(subjectString, wordtofind, replacement){
    var escapedWord = EscapeRegex(wordtofind);
    //simplest scenaro, word to find has non-word characters at begining and end - do basic replace
    if(regexIndexOf(escapedWord, '[^\\w]', 0) == 0 && regexLastIndexOf(escapedWord, '[^\\w]', 0) == wordtofind.length - 1){
        subjectString = subjectString.replace(new RegExp(escapedWord, 'g'), replacement);
    }
    //word to find begins with non-wordcharacter
    else if(regexIndexOf(escapedWord, '[^\\w]', 0) == 0){
        var index = regexIndexOf(subjectString, escapedWord+'[^\\w]', index);
        while(index > 0){
            subjectString = subjectString.substring(0, index) + replacement + subjectString.substring(index + wordtofind.length);
            index = regexIndexOf(subjectString, escapedWord+'[^\\w]', index);
        }
    }
    //word to find ends with non-wordcharacter
    else if(regexLastIndexOf(escapedWord, '[^\\w]', 0) == wordtofind.length - 1){
        var index = regexIndexOf(subjectString, '[^\\w]'+escapedWord, index);
        while(index > 0){
            subjectString = subjectString.substring(0, index) + replacement + subjectString.substring(index + myword.length + 1);
            index = regexIndexOf(subjectString, escapedWord+'[^\\w]', index);
        }
    }
    //word is normal
    else{
        var index = regexIndexOf(subjectString,'[^\\w]'+escapedWord+'[^\\w]', index);
        while(index >= 0){
            subjectString = subjectString.substring(0, index + 1) + replacement + subjectString.substring(index + wordtofind.length + 1);
            index = regexIndexOf(subjectString,'[^\\w]'+escapedWord+'[^\\w]', index);
        }
    }
    return subjectString;
}