How to insert a variable in a regex?

Question

var adjectives = "blue|pretty|big";
regex = /blue is an adjective/i;

Let's say I need to use the adjectives above multiple times. So, instead of doing:
var chance1 = /(blue|pretty|big) is an adjective/i;
var chance2 = /(blue|pretty|big) is definitely an adjective/i;
var chance3 = /(blue|pretty|big) is adjective/i;

Instead I want to do something like

var chance1 = /(+adjectives+) is an adjective/i;
var chance 2 = /(+adjectives+) is definitely an adjective/i; ...

note: in the above code, the variable adjectives contains the adjectives: blue, pretty, blue...

That's an example.
So, how do we use a variable inside a regex?

Answer 1

You will have to use the RegExp constructor along with concatenation or template literals.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#Constructor

https://code.sololearn.com/WCuv7oJLB0aT/#js