javascript - match string against the array of regular expressions

Question

Is there a way in JavaScript to get Boolean value for a match of the string against the array of regular expressions?

The example would be (where the \'if\' statemen

Answer 1

Using a more functional approach, you can implement the match with a one-liner using an array function:

ECMAScript 6:

const regexList = [/apple/, /pear/];
const text = "banana pear";
const isMatch = regexList.some(rx => rx.test(text));

ECMAScript 5:

var regexList = [/apple/, /pear/];
var text = "banana pear";
var isMatch = regexList.some(function(rx) { return rx.test(text); });

Answer 2

look this way...

function matchInArray(stringSearch, arrayExpressions){
    var position = String(arrayExpressions).search(stringSearch);
    var result = (position > -1) ? true : false
    return result;
}

Answer 3

let expressions = [ '/something/', '/something_else/', '/and_something_else/'];

let str = 'else';

here will be the check for following expressions:

if( expressions.find(expression => expression.includes(str) ) ) {

}

using Array .find() method to traverse array and .include to check substring

Answer 4

http://jsfiddle.net/9nyhh/1/

var thisExpressions = [/something/, /something_else/, /and_something_else/];
var thisExpressions2 = [/else/, /something_else/, /and_something_else/];
var thisString = 'else';

function matchInArray(string, expressions) {

    var len = expressions.length,
        i = 0;

    for (; i < len; i++) {
        if (string.match(expressions[i])) {
            return true;
        }
    }

    return false;

};

setTimeout(function() {
    console.log(matchInArray(thisString, thisExpressions));
    console.log(matchInArray(thisString, thisExpressions2));
}, 200)​

Answer 5

So we make a function that takes in a literal string, and the array we want to look through. it returns a new array with the matches found. We create a new regexp object inside this function and then execute a String.search on each element element in the array. If found, it pushes the string into a new array and returns.

// literal_string: a regex search, like /thisword/ig
// target_arr: the array you want to search /thisword/ig for.

function arr_grep(literal_string, target_arr) {
  var match_bin = [];
  // o_regex: a new regex object.
  var o_regex = new RegExp(literal_string);
  for (var i = 0; i < target_arr.length; i++) {
    //loop through array. regex search each element.
    var test = String(target_arr[i]).search(o_regex);
    if (test > -1) {
    // if found push the element@index into our matchbin.
    match_bin.push(target_arr[i]);
    }
  }
  return match_bin;
}

// arr_grep(/.*this_word.*/ig, someArray)

Answer 6

You can join all regular expressions into single one. This way the string is scanned only once. Even with a sligthly more complex regular expression.

var thisExpressions = [ /something/, /something_else/, /and_something_else/];
var thisString = 'else';


function matchInArray(str, expr) {
    var fullExpr = new RegExp(expr
        .map(x=>x.source) // Just if you need to provide RegExp instances instead of strings or ...
        // .map(x=>x.substring(1, x.length -2)  // ...if you need to provide strings enclosed by "/" like in original question.
        .join("|")
    )
    return str.match(fullExpr);

};


if (matchInArray(thisString, thisExpressions)) {
    console.log ("Match!!");
} 

In fact, even with this approach, if you need check the same expression set against multiple strings, this is a few suboptimal because you are building (and compiling) the same regular expression each time the function is called.

Better approach would be to use a function builder like this:

var thisExpressions = [ /something/, /something_else/, /and_something_else/];
var thisString = 'else';

function matchInArray_builder(expr) {
    var fullExpr = new RegExp(expr
        .map(x=>x.source) // Just if you need to provide RegExp instances instead of strings or ...
        // .map(x=>x.substring(1, x.length -2)  // ...if you need to provide strings enclosed by "/" like in original question.
        .join("|")
    )   

    return function (str) {
        return str.match(fullExpr);

    };
};  

var matchInArray = matchInArray_builder(thisExpressions);

if (matchInArray(thisString)) {
    console.log ("Match!!");
}