JavaScript regex.exec() should intended to use an assembled regEx-CodePudding

if I use ( https://jsfiddle.net/fgsvzn4a/ ) :

var text = "ui1pu";
var regExParameter = '\d ';
var regEx = '/(.*)'   regExParameter   '(.*)/gi';
var matches = regEx.exec(text);
if(matches && matches[1]) {
    var str1 = matches[1];
    var str2 = matches[2];
    var newStr = str1   str2
    console.log(newStr);
}

i get this error:

Paused on exception
TypeError: regEx.exec is not a function

this prototype is working (inspired by https://stackoverflow.com/a/15845184/2891692 ):

var text = "my1bla";
var matches = /(my)\d (.*)/gi.exec(text);
if(matches && matches[1]) {
var str1 = matches[1];
var str2 = matches[2];
var newStr = str1   str2
alert(newStr);
}

but i want to use input parameters to build the regex (first example).

i get ReferenceError: Regex is not defined if i try this:

var text = "ui1pu";
var regExParameter = '\d ';
var regExString = '/(.*)'   regExParameter   '(.*)/gi';
var regEx = new Regex(regExString);
var matches = regEx.exec(text);
if(matches && matches[1]) {
    var str1 = matches[1];
    var str2 = matches[2];
    var newStr = str1   str2
    console.log(newStr);
}

any idea?

CodePudding user response：

Use the RegExp constructor. Note that the slashes should be omitted from the string and the flags should be passed as the second argument.

var text = "ui1pu";
var regExParameter = '\\d ';
var regExString = '(.*)'   regExParameter   '(.*)';
var regEx = new RegExp(regExString, 'gi');
var matches = regEx.exec(text);
if(matches && matches[1]) {
    var str1 = matches[1];
    var str2 = matches[2];
    var newStr = str1   str2
    console.log(newStr);
}