Assuming you always want to cut it off just before the first number, you could find the index of the first number:

const index = 'total sales 234 rs'.search(/\d/);

And then just get the substring:

substring(0, index - 1);

You can do something like this:

let str = 'total sales 234 rs';
let result = str.split(' ').slice(0,2).join(' ');

Assuming that the string can contain more than two main words For eg Total goods cost 200 rs

then use the below function

function reducer(str) { // where str is the initial string
 const modifiedStr = str.split(' ').reduce((acc, substr) => {
  if(!parseInt(substr, 10) && substr !== 'rs') acc+=substr+' ';
  return acc;
 }, "");
 return modifiedStr.slice(0,modifiedStr.length - 2);
}