URL: canParse() static method
Baseline 2023
Newly available
Since December 2023, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
Note: This feature is available in Web Workers.
The URL.canParse()
static method of the URL
interface returns a boolean indicating whether or not an absolute URL, or a relative URL combined with a base URL, are parsable and valid.
This is a fast and easy alternative to constructing a URL
within a try...catch block.
It returns true
for the same values for which the URL()
constructor would succeed, and false
for the values that would cause the constructor to throw.
Syntax
URL.canParse(url)
URL.canParse(url, base)
Parameters
url
-
A string or any other object with a stringifier — including, for example, an
<a>
or<area>
element — that represents an absolute or relative URL. Ifurl
is a relative URL,base
is required, and will be used as the base URL. Ifurl
is an absolute URL, a givenbase
will be ignored. base
Optional-
A string representing the base URL to use in cases where
url
is a relative URL. If not specified, it defaults toundefined
.
Return value
true
if the URL can be parsed and is valid; false
otherwise.
Examples
This live example demonstrates how to use the URL.canParse()
static method for a few different absolute and relative URL values.
The first part of the example defines an HTML <pre>
element to log to, along with a logging method log()
.
<pre id="log"></pre>
const logElement = document.getElementById("log");
function log(text) {
logElement.innerText += `${text}\n`;
}
Next we check that the URL.canParse()
method is supported using the condition "canParse" in URL
.
If the method is supported we log the result of checking an absolute URL, a relative URL with no base URL, and a relative URL with a valid base URL.
We also log the case when URL.canParse()
is not supported.
if ("canParse" in URL) {
log("Test valid absolute URL");
let url = "https://developer.mozilla.org/";
let result = URL.canParse(url);
log(` URL.canParse("${url}"): ${result}`);
log("\nTest relative URL with no base URL");
url = "/en-US/docs";
result = URL.canParse(url);
log(` URL.canParse("${url}"): ${result}`);
log("\nTest relative URL with valid base URL");
let baseUrl = "https://developer.mozilla.org/";
result = URL.canParse(url, baseUrl);
log(` URL.canParse("${url}","${baseUrl}"): ${result}`);
} else {
log("URL.canParse() not supported");
}
Last of all, the code below shows that the baseUrl
doesn't have to be a string.
Here we have passed a URL
object.
if ("canParse" in URL) {
log("\nTest relative URL with base URL supplied as a URL object");
let baseUrl = new URL("https://developer.mozilla.org/");
let url = "/en-US/docs";
result = URL.canParse(url, baseUrl);
log(` URL.canParse("${url}","${baseUrl}"): ${result}`);
}
The results of each of the checks are shown below.
Specifications
Specification |
---|
URL Standard # dom-url-canparse |
Browser compatibility
BCD tables only load in the browser
See also
URL()
- A polyfill of
URL.canParse()
is available incore-js