Javascript RegEx Help

Question

I want to take strings like:

• Submit Changes
• Create New
• Update Record
• Save Item

and convert them to:

• Submitting Changes
• Creating New
• Updating Record
• Saving Item

with a function like:

var ConvertToProgressivePresent = (function(){
    // cache this regex
    var rProgressivePresent = /\b(?:(Submi(t))|(Creat|Sav|Updat)e)\b/i;
    return function(phrase){
        return phrase.replace(rProgressivePresent, "$1$2$3ing");
    };
}());

This above regex works but doesn't seem like the best way to do it. I don't like the grouping here where 1-2 groups are always empty when there is a match.

Got any suggestions or improvements?

Answer 1

I think you should probablly use CASE statments instead. Regex isn't the most efficient way of doing things...and that is probably best that it doesn't cuz you know the old saying.

Wow, I have this problem...I know, I'll use regex...ok, now you have two problems 90)

Answer 2

First off, it doesn't appear to me that your regex does quite what you want anyway in that I don't see a second "t" added when changing submit to submitting.

However, I don't think I would use regex for this task at all anyway. If you are just trying to replace one word with another, and the word always comes at the beginning of the string, I might do something like:

function ReplaceIfBeginsWith(wholeString, checkFor, replaceWith)
{
    if (wholeString.indexOf(checkFor + ' ') == 0)
    {
        return replaceWith + ' ' + wholeString.substr(checkFor.length + 1);
    }
    if (wholeString == checkFor)
    {
        return replaceWith;
    }
    return wholeString;
}

Then, you can call the function with each of the words you would want to replace. If you want case-insensitivity, just check against lowercase versions of all the strings.

Answer 3

If you have specific words to replace with then you could make a word bank. Have the words and their replacement stored in an object and then loop through it.

var ConvertToProgressivePresent = (function() {
    var replaceValues = {
        "Submit": "Submitting",
        "Create": "Creating",
        "Update": "Updating",
        "Save": "Saving"
    }
    return function(phrase) {
        for (var item in replaceValues) {
            phrase = phrase.replace(item, replaceValues[item]);
        }
        return phrase;
    };
}());

Here is a JSFiddle Example