Question

I have a bunch of regular expression, e.g. /[a-z]/. Later in my program I need to have this as /[a-z]/g,
so I need to add the ‘global’ modifier later. How can I add a modifier to an existing regular expression?

Answer 1

Use RegEx source and flags to separate the regular expression from the flags. Then create a new one with the string and set the needed flags.

var re = /^[a-z]*$/;
var re2 = new RegExp(re.source, re.flags + "i");

console.log( re.test("abc") )
console.log( re.test("ABC") )
console.log( re2.test("abc") )
console.log( re2.test("ABC") )