requireUrl

function requireUrl(value: unknown, message: string = "Expected a valid URL."): string;

An http, https or ftp URL with something after the scheme and no whitespace anywhere. A bare host such as "example.com" is not one.

isX and nonX answer a question and never interrupt control flow; requireX and requireNonX hand the value back or throw. The scheme is explained in Validation conventions.

Parameters

Parameter	Type	Description
`value`	`unknown`	The value to validate.
`message` (optional) `= "Expected a valid URL."`	`string`	The message of the exception. A default is used when omitted.

Returns

string — the same value, typed as a URL.

Throws

Exception	Condition
`IllegalArgumentException`	the value is not a URL.

Examples

What passes and what does not

requireUrl("https://example.com"); // => "https://example.com"
requireUrl("http://example.com/a?b=1"); // => "http://example.com/a?b=1"
requireUrl("example.com"); // throws IllegalArgumentException
requireUrl("https://"); // throws IllegalArgumentException

Source

src/net/url/requireUrl.ts

23 September 2026

This documentation was generated with AI (Claude) from the library's source code.

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