Check whether a string matches a regex in JS
JavascriptRegexMatchJavascript Problem Overview
I want to use JavaScript (can be with jQuery) to do some client-side validation to check whether a string matches the regex:
^([a-z0-9]{5,})$
Ideally it would be an expression that returned true or false.
I'm a JavaScript newbie, does match() do what I need? It seems to check whether part of a string matches a regex, not the whole thing.
Javascript Solutions
Solution 1 - Javascript
Use regex.test() if all you want is a boolean result:
console.log(/^([a-z0-9]{5,})$/.test('abc1')); // false
console.log(/^([a-z0-9]{5,})$/.test('abc12')); // true
console.log(/^([a-z0-9]{5,})$/.test('abc123')); // true
...and you could remove the () from your regexp since you've no need for a capture.
Solution 2 - Javascript
Use test() method :
var term = "sample1";
var re = new RegExp("^([a-z0-9]{5,})$");
if (re.test(term)) {
console.log("Valid");
} else {
console.log("Invalid");
}
Solution 3 - Javascript
You can use match() as well:
if (str.match(/^([a-z0-9]{5,})$/)) {
alert("match!");
}
But test() seems to be faster as you can read here.
Important difference between match() and test():
match() works only with strings, but test() works also with integers.
12345.match(/^([a-z0-9]{5,})$/); // ERROR
/^([a-z0-9]{5,})$/.test(12345); // true
/^([a-z0-9]{5,})$/.test(null); // false
// Better watch out for undefined values
/^([a-z0-9]{5,})$/.test(undefined); // true
Solution 4 - Javascript
Use /youregexp/.test(yourString) if you only want to know whether your string matches the regexp.
Solution 5 - Javascript
let str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
let regexp = /[a-d]/gi;
console.log(str.match(regexp));
Solution 6 - Javascript
Here's an example that looks for certain HTML tags so it's clear that /someregex/.test() returns a boolean:
if(/(span|h[0-6]|li|a)/i.test("h3")) alert('true');
Remember to indicate ^ for beginning of the string and $ for the end, if you want to test the exact match of entire string.
Example:
/[a-z]+/.test('aaa111'); // true
/^[a-z]+$/.test('aaa111'); // false
Solution 7 - Javascript
const regExpStr = "^([a-z0-9]{5,})$"
const result = new RegExp(regExpStr, 'g').test("Your string") // here I have used 'g' which means global search
console.log(result) // true if it matched, false if it doesn't
Solution 8 - Javascript
try
/^[a-z\d]{5,}$/.test(str)
console.log( /^[a-z\d]{5,}$/.test("abc123") );
console.log( /^[a-z\d]{5,}$/.test("ab12") );
Solution 9 - Javascript
I would recommend using the execute method which returns null if no match exists otherwise it returns a helpful object.
let case1 = /^([a-z0-9]{5,})$/.exec("abc1");
console.log(case1); //null
let case2 = /^([a-z0-9]{5,})$/.exec("pass3434");
console.log(case2); // ['pass3434', 'pass3434', index:0, input:'pass3434', groups: undefined]
Solution 10 - Javascript
You can try this, it works for me.
<input type="text" onchange="CheckValidAmount(this.value)" name="amount" required>
<script type="text/javascript">
function CheckValidAmount(amount) {
var a = /^(?:\d{1,3}(?:,\d{3})*|\d+)(?:\.\d+)?$/;
if(amount.match(a)){
alert("matches");
}else{
alert("does not match");
}
}
</script>
Solution 11 - Javascript
please try this flower:
/^[a-z0-9\_\.\-]{2,20}\@[a-z0-9\_\-]{2,20}\.[a-z]{2,9}$/.test('[email protected]');
> true
Solution 12 - Javascript
If you don't want ^ and $ around the regex (I had such a usecase) you can do something like
let reg = /[a-zA-Z0-9]+/g
let txt = "hello"
let matches = reg.exec(txt)[0] == txt
console.log(`It ${matches ? "does" : "doesn't"} match`)