Javascript RegEx Remove Multiple words from string

Question

Using Javascript. ( note there is a similar post , but the OP requested Java, this is for Javascript )

I'm trying to remove a list of words from an entire string without looping (preferably using Regular Expressions).

This is what I have so far, and it removes some of the words but not all of them. Can someone help identify what I'm doing wrong with my RegEx function?

  //Remove all instances of the words in the array var removeUselessWords = function(txt) { var uselessWordsArray = [ "a", "at", "be", "can", "cant", "could", "couldnt", "do", "does", "how", "i", "in", "is", "many", "much", "of", "on", "or", "should", "shouldnt", "so", "such", "the", "them", "they", "to", "us", "we", "what", "who", "why", "with", "wont", "would", "wouldnt", "you" ]; var expStr = uselessWordsArray.join(" | "); return txt.replace(new RegExp(expStr, 'gi'), ' '); } var str = "The person is going on a walk in the park. The person told us to do what we need to do in the park"; console.log(removeUselessWords(str)); //The result should be: "person going walk park. person told need park." 

Answer 1

Three moments:

• join array items with | without side spaces
• enclose regex alternation group into parentheses (...|...)
• specify word boundary \\b to match a separate words

 var removeUselessWords = function(txt) { var uselessWordsArray = [ "a", "at", "be", "can", "cant", "could", "couldnt", "do", "does", "how", "i", "in", "is", "many", "much", "of", "on", "or", "should", "shouldnt", "so", "such", "the", "them", "they", "to", "us", "we", "what", "who", "why", "with", "wont", "would", "wouldnt", "you" ]; var expStr = uselessWordsArray.join("|"); return txt.replace(new RegExp('\\\\b(' + expStr + ')\\\\b', 'gi'), ' ') .replace(/\\s{2,}/g, ' '); } var str = "The person is going on a walk in the park. The person told us to do what we need to do in the park"; console.log(removeUselessWords(str)); 

Answer 2

May be this is what you want:

  //Remove all instances of the words in the array var removeUselessWords = function(txt) { var uselessWordsArray = [ "a", "at", "be", "can", "cant", "could", "couldnt", "do", "does", "how", "i", "in", "is", "many", "much", "of", "on", "or", "should", "shouldnt", "so", "such", "the", "them", "they", "to", "us", "we", "what", "who", "why", "with", "wont", "would", "wouldnt", "you" ]; var expStr = uselessWordsArray.join("\\\\b|\\\\b"); return txt.replace(new RegExp(expStr, 'gi'), '').trim().replace(/ +/g, ' '); } var str = "The person is going on a walk in the park. The person told us to do what we need to do in the park"; console.log(removeUselessWords(str)); //The result should be: "person going walk park. person told need park."