JavaScript str.replace用变量

Question

I have found a short script which finds a line with a certain phrase in it and replaces the whole line with a new line. However I can't work out how to include a variable where it says '#RemoveMe' in the str.replace. (I want to include the variable 'start' which is passed in by the function's trigger, to make --> (/^. start. $/mg, ""))

Any help appreciated...

        var str = 'line1\n'+
          'line2\n'+
          '#RemoveMe line3\n'+
          'line4';

        var test = str.replace(/^.*#RemoveMe.*$/mg, "");

Thanks.

Answer 1

This is a limitation of the inline regular expression notation.

If you use new RegExp() you can pass the expression as a string.

var find = "start";
var regexp = new RegExp("^.*" + find + ".*$", "mg"); // note: no delimiters
str.replace(regexp, "");