javascript - Is there any easier or shorter way to write this repeat code? -

i wondering if there shorter/ easier way write repeating code. if name entered prompt box doesn't have send error message , reput it.

just dont have explain alot, heres code:

function error() {     alert('you must enter name.'); }  var name = prompt('what name?', 'name');  function repeat() {     var name = prompt('what name?', 'name');     if(name === '') {         error();         repeat();     } }  if(name === '') {     error();     repeat(); } 

like this:

var name;    while(!(name=prompt('what name?', 'name'))) {    alert('you must enter name.');  }

how works

the while loop repeats until condition met. in case, condition is:

!(name=prompt('what name?', 'name')) 

this part of expression assigns prompt value name (as you're aware):

name=prompt('what name?', 'name') 

in javascript, assignment variable returns value. (that's why can chain assignments such a = b = c = 16.)

so if enter "johnathan" name, expression becomes "johnathan":

(name=prompt('what name?', 'name')) 

if enter nothing name, expression becomes null string.

the logical not operator (!) before expression returns boolean opposite of "truthiness" of expression. string value truthy, null string falsy.

by applying not operator expression:

!(name=prompt('what name?', 'name')) 

… loop continue until name variable has value.

final thought: convention, variables should begin lowercase letter. haven't done here, because name property of window, , changing window's name lead problems. ideally, prompt within function, wouldn't have global variables. if case, use variable name others have suggested.