Check if string contains word (not substring)

Question

I am trying to check if a string contains a particular word, not just a substring.

Here are some sample inputs/outputs:

var str = "This is a cool area!";
containsWord(str, "is"); // return true
containsWord(str, "are"); // return false
containsWord(str, "area"); // return true

The following function will not work as it will also return true for the second case:

function containsWord(haystack, needle) {
     return haystack.indexOf(needle) > -1;
}

This also wouldn't work as it returns false for the third case:

function containsWord(haystack, needle) {
     return (' ' +haystack+ ' ').indexOf(' ' +needle+ ' ') > -1;
}

How do I check if a string contains a word then?

Answer 1

Try using regex for that, where the \b metacharacter is used to find a match at the beginning or end of a word.

var str = "This is a cool area!";

function containsWord(str, word) {
  return str.match(new RegExp("\\b" + word + "\\b")) != null;
}

console.info(containsWord(str, "is")); // return true
console.info(containsWord(str, "are")); // return false
console.info(containsWord(str, "area")); // return true

Answer 2

You can remove all special characters and then split string with space to get list of words. Now just check id searchValue is in this word list

function containsWord(str, searchValue){
  str = str.replace(/[^a-z0-9 ]/gi, '');
  var words = str.split(/ /g);
  return words.indexOf(searchValue) > -1
}

var str = "This is a cool area!";
console.log(containsWord(str, "is")); // return true
console.log(containsWord(str, "are")); // return false
console.log(containsWord(str, "area")); // return true