regex - javascript regexp both character is optional but merely one is invalid -


i have string checking regular expression in javascript. string can contain +8 or 8 or can empty string. cannot contain merely + sign.

these valid: +8 or 8 or ( 3rd 1 indicates empty string)

this invalid: +

the code have tried:

var x=/^\+?(8)?$/.test("+8")? 'ok':'not'; document.write(x);

everything ok code. problem that, code returns true if string contains only + sign, should false. how implement have wanted?

try -

^(\+?8)?$

testing - 

> /^(\+?8)?$/.test("+")? 'ok':'not'; "not" > /^(\+?8)?$/.test("+8")? 'ok':'not'; "ok" > /^(\+?8)?$/.test("")? 'ok':'not'; "ok"

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