javascriptregexstring

javascript includes() case insensitive

Need to loop an array of strings and check against with another string, which is passed in the string.

var filterstrings = ['firststring','secondstring','thridstring'];
var passedinstring = localStorage.getItem("passedinstring");

for (i = 0; i < filterstrings.lines.length; i++) {
    if (passedinstring.includes(filterstrings[i])) {
        alert("string detected");
    }
}

How do I ensure that it's case insensitive(preferably by using regex) when filtering, if the var passedinstring were to have strings like FirsTsTriNg or fiRSTStrING?

Solution

  • You can create a RegExp from filterstrings first

    var filterstrings = ['firststring','secondstring','thirdstring'];
var regex = new RegExp( filterstrings.join( "|" ), "i");

    then test if the passedinstring is there

    var isAvailable = regex.test( passedinstring );

    Here is a test implementation:

    // Take care to escape these strings!
// If they are user-input or may contain special regex characters (such as "$" or "."), they have to be escaped.
var filterStrings = ['one','two','three'];
var regex = new RegExp(filterStrings.join( "|" ), "i");

var sentences = [
  "one", // true
  "OnE", // true
  "a rabbit", // false
  "and then two rabbits", // true
  "standing", // false
  "prone", // true
  "AoNeAtWo", // true
];
sentences.forEach(sentence => {
  console.log(
    regex.test(sentence) ? '✅ match:' : '❌ not a match:',
    "'" + sentence + "'",
    );
});