I am using indexOf to see if an email contains anything other than a particular text.
For example, I want to check if an email DOES NOT include "usa" after the @ symbol, and display an error message.
I was first splitting the text and removing everything before the @ symbol:
var validateemailaddress = regcriteria.email.split('@').pop();
Then, I check if the text doesn't include "usa":
if(validateemailaddress.indexOf('usa')){
$('#emailError').show();
}
Something with the above check doesn't seem right. It works - I can enter an email, and if it does not include 'usa', then the error message will show.
Regardless, when I add an additional check, like if the email does not include "can", then the error message shows no matter what.
As follows:
if(validateemailaddress.indexOf('usa') || validateemailaddress.indexOf('can')){
$('#emailError').show();
}
As stated, using the above, the error message will show regardless if the email includes the text or not.
All I want to do is check if the email includes 'usa' or 'can', and if it doesn't, then show the error message.
How can I make this work?
Here is a simple JavaScript function to check if an email address contains 'usa' or 'can'.
function emailValid(email, words) {
// Get the position of @ [indexOfAt = 3]
let indexOfAt = email.indexOf('@');
// Get the string after @ [strAfterAt = domain.usa]
let strAfterAt = email.substring(indexOfAt + 1);
for (let index in words) {
// Check if the string contains one of the words from words array
if (strAfterAt.includes(words[index])) {
return true;
}
}
// If the email does not contain any word of the words array
// it is an invalid email
return false;
}
let words = ['usa', 'can'];
if (!emailValid('abc@domain.usa', words)) {
console.log("Invalid Email!");
// Here you can show the error message
} else {
console.log("Valid Email!");
}There are several ways to check, if a string contains/does not contain a substring.
String.prototype.includes
'String'.includes(searchString); // returns true/false
String.prototype.indexOf
// returns values from -1 to last postion of string.
'String'.indexOf(searchString);
// In combination with ~ this can work similar to includes()
// for strings up to 2^31-1 byte length
// returns 0 if string is not found and -pos if found.
~'String'.indexOf(searchString);
With the help of Regular Expressions:
// substring must be escaped to return valid results
new RegExp(escapedSearchString).test('String'); // returns true/false if the search string is found
'String'.match(escapedSearchString); // returns null or an array if found
So overall you can use allmost all methods like:
if ('String'.function(searchString)) {
// 'String' includes search String
} else {
// 'String' does not include search String
}
Or in case of indexOf:
if ('String'.indexOf(searchString) > -1) {
// 'String' includes search String
} else {
// 'String' does not include search String
}
// OR
if (~'String'.indexOf(searchString)) {
// 'String' includes search String
} else {
// 'String' does not include search String
}
You can do something like that, using includes:
const validateEmailAdress = (email) => {
const splittedEmail = email.split('@').pop();
return (splittedEmail.includes('usa') || splittedEmail.includes('can'))
}
console.log("Includes usa: ", validateEmailAdress("something@gmail.usa"))
console.log("Includes can: ", validateEmailAdress("something@gmail.can"))
console.log("Does not includes: ", validateEmailAdress("something@gmail.com"))