如何通过白名单域名正则表达式验证电子邮件

Question

I want to validate domain by whitelist such as : .com , .co.id, .org,

here i have a regex pattern :

/^[_a-z0-9-]+(\\.[_a-z0-9-]+)*(\\+[a-z0-9-]+)?@[a-z0-9-]+(\\.[a-z0-9-]+)*$/i;

so if the user input :

• example@example.gov -> invalid
• example@example.com -> valid

anyone can help me out ? Thank you

Answer 1

Try this

 let e = ["example@example.gov", "example@example.com", "example@example.co.id", "example@example.org"]; let d = [".com", ".co.id", ".org"]; let f = x=> d.some(y => new RegExp(`@.*?(${y})`).test(x)); let v = e.filter(x=> f(x)); console.log(v); // show valid emails 

Explanation : of regexp: It match the letters after first dot after @ . First we get any characters after @ in non-greedy way by .*? then we open group ( before first dot \\. and check that all left characters are domain ${y}) .

Answer 2

You can proceed in two steps:

• Check that the email is well formed -> example: https://www.regular-expressions.info/email.html , there are many sources on this subject

• Validate that the domain is in the whitelist of domains

 function validateEmail(email) { //check that the input string is an well formed email var emailFilter = /^([a-zA-Z0-9_.-])+@(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/; if (!emailFilter.test(email)) { return false; } //check that the input email is in the whitelist var s, domainWhitelist = [".com", "co.id", ".org"]; for (s of domainWhitelist) if(email.endsWith(s)) return true; //if we reach this point it means that the email is well formed but not in the whitelist return false; } console.log("validate ->" + validateEmail("")); console.log("validate abc ->" + validateEmail("abc")); console.log("validate example@example.gov ->" + validateEmail("example@example.gov")); console.log("validate example@example.com ->" + validateEmail("example@example.com"));