Trim twice or trim and assign to a variable which will be more faster in perfomance, javascript

I have a email validation fuction where i need to trim string value twice.

(val) => (val.trim() && emailReg.test(val.trim()))

Or

(val) => { 
   const value = val.trim();
     return value &&emailReg.test(value) 
}

which is more faster and meet coding standards.