API reference › @evolu/common › Type › UrlFromString

const UrlFromString: transform(
  "UrlFromString",
  String,
  Url,
  {
    from: (value: string): Result<string, UrlFromStringError> => {
      const canonical = canonicalizeUrl(value);
      return canonical === undefined
        ? err({ type: "UrlFromString", value })
        : ok(canonical);
    },
    to: (value: Url) => value,
  },
  formatUrlFromStringError,
);

Defined in: packages/common/src/Type.ts:9764

Transforms an absolute URL into its canonical Url.

Accepts what the platform's URL parses without a base URL, as Url describes, and returns its href. Encoding returns the canonical spelling, not the original one.

Example

import { assertEqual, assertErr, assertOk, UrlFromString } from "@evolu/common";

// Lowercases the scheme and host, removes 443, the default port of https:,
// and resolves /a/../b to /b.
assertOk(
  UrlFromString.fromUnknown("HTTPS://Example.com:443/a/../b"),
  "https://example.com/b",
);

const invalid = UrlFromString.fromUnknown("/b");
assertErr(invalid, { type: "UrlFromString", value: "/b" });
assertEqual(
  UrlFromString.formatError(invalid.error),
  'The value "/b" is not a valid URL.',
);
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