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How to check if a string contain specific words?

$a = 'how are you';
if (strpos($a,'are') !== false) {
    echo 'true';
}

In PHP, we can use the code above to check if a string contain specific words, but how can I do the same function in JavaScript/jQuery?

over 4 years ago · Santiago Trujillo

3 answers

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you can use indexOf for this

var a = 'how are you';
if (a.indexOf('are') > -1) {
  return true;
} else {
  return false;
}

Edit: This is an old answer that keeps getting up votes every once in a while so I thought I should clarify that in the above code, the if clause is not required at all because the expression itself is a boolean. Here is a better version of it which you should use,

var a = 'how are you';
return a.indexOf('are') > -1;

Update in ECMAScript2016:

var a = 'how are you';
return a.includes('are');  //true

over 4 years ago · Santiago Trujillo Report

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`indexOf`/`includes` should not be used for finding whole words:

A word (in western culture) is a drawing of a symbols close to each other, with some space between each word. A word is considered as such if it's a complete piece of characters draw together and not a partial part of it:

"has a word".indexOf('wor')  // 6 ("wor" is not a word in this sentence)
"has a word".includes('ha') // true ("ha" is not a word in this sentence)

Check if a single word (whole word) is in the string

Find a real whole word, not just if the letters of that word are somewhere in the string.

const wordInString = (s, word) => new RegExp('\\b' + word + '\\b', 'i').test(s);

// tests
[
  '',            // true
  ' ',           // true
  'did',         // true
  'id',          // flase
  'yo ',         // flase
  'you',         // true
  'you not'      // true
].forEach(q => console.log(
  wordInString('dID You, or did you NOt, gEt WHy?', q) 
))

console.log(
  wordInString('did you, or did you not, get why?', 'you') // true
)

Check if all words are in the string

var stringHasAll = (s, query) => 
  // convert the query to array of "words" & checks EVERY item is contained in the string
  query.split(' ').every(q => new RegExp('\\b' + q + '\\b', 'i').test(s)); 


// tests
[
  '',            // true
  ' ',           // true
  'aa',          // true
  'aa ',         // true
  ' aa',         // true
  'd b',         // false
  'aaa',         // false
  'a b',         // false
  'a a a a a ',  // false
].forEach(q => console.log(
  stringHasAll('aA bB cC dD', q) 
))

over 4 years ago · Santiago Trujillo Report

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Accepted Answer · 2022-05-24T14:28:08.314Z

If you are looking for exact words and don't want it to match things like "nightmare" (which is probably what you need), you can use a regex:

/\bare\b/gi

\b = word boundary
g = global
i = case insensitive (if needed)

If you just want to find the characters "are", then use indexOf.

If you want to match arbitrary words, you have to programatically construct a RegExp (regular expression) object itself based on the word string and use test.

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