data-urls 7.x

Complete instructions

Verified against data-urls@7.0.0 on 2026-09-08. 6 of 6 examples executed.

data-urls

Use this skill for data-urls@^7.0.0.

Surface

The default export is callable:

const parseDataURL = require("data-urls");
const result = parseDataURL(input);

It returns either:

• { mimeType, body }, where mimeType is a whatwg-mimetype MIMEType and body is a Uint8Array.
• null when the input cannot be parsed as a data: URL.

The named fromURLRecord export accepts a whatwg-url URL record:

const { fromURLRecord } = require("data-urls");
const { parseURL } = require("whatwg-url");
const result = fromURLRecord(parseURL("data:,Hello"));

Important version differences

• In v7, the main export is directly callable and returns { mimeType, body } or null. Do not use an older API shape from examples that returns or requires a different parser object.
• The runtime floor declared by v7 is ^20.19.0 || ^22.12.0 || >=24.0.0.
• The v7 dependency generations are whatwg-mimetype ^5.0.0 and whatwg-url ^16.0.0.
• For decoding the returned bytes, v7 documents TextDecoder. Older examples using whatwg-encoding are not the documented v7 approach.

Parse ordinary text data URLs

A missing media type receives the MIME type shown below. Percent escapes in the payload are decoded into bytes.

import assert from "node:assert/strict";
import parseDataURL from "data-urls";

const result = parseDataURL("data:,Hello%2C%20World!");

assert.notEqual(result, null);
assert.equal(result.mimeType.toString(), "text/plain;charset=US-ASCII");
assert.deepEqual([...result.body], [...new TextEncoder().encode("Hello, World!")]);

A declared MIME type is preserved in the returned MIMEType object.

import assert from "node:assert/strict";
import parseDataURL from "data-urls";

const result = parseDataURL("data:text/html,%3Ch1%3EHello%2C%20World!%3C%2Fh1%3E");

assert.notEqual(result, null);
assert.equal(result.mimeType.toString(), "text/html");
assert.equal(new TextDecoder().decode(result.body), "<h1>Hello, World!</h1>");

Parse base64 data URLs

Use the ;base64 marker in the metadata portion. The result body remains a Uint8Array.

import assert from "node:assert/strict";
import parseDataURL from "data-urls";

const result = parseDataURL(
  "data:image/png;base64,iVBORw0KGgoAAA" +
  "ANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4" +
  "//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU" +
  "5ErkJggg=="
);

assert.notEqual(result, null);
assert.equal(result.mimeType.toString(), "image/png");
assert.ok(result.body instanceof Uint8Array);
assert.deepEqual([...result.body.slice(0, 8)], [137, 80, 78, 71, 13, 10, 26, 10]);
assert.equal(result.body.length, 85);

Handle invalid input

Check for null before accessing mimeType or body.

import assert from "node:assert/strict";
import parseDataURL from "data-urls";

assert.equal(parseDataURL("https://example.com/resource"), null);
assert.equal(parseDataURL("not a URL"), null);

Parse from a URL record

Use fromURLRecord when the caller already has a whatwg-url URL record. A string should be passed to the default export instead.

import assert from "node:assert/strict";
import dataURLs from "data-urls";
import { parseURL } from "whatwg-url";

const urlRecord = parseURL("data:,Hello%2C%20World!");
assert.notEqual(urlRecord, null);

const result = dataURLs.fromURLRecord(urlRecord);
assert.notEqual(result, null);
assert.equal(result.mimeType.toString(), "text/plain;charset=US-ASCII");
assert.equal(new TextDecoder().decode(result.body), "Hello, World!");

Decode bytes as text

Parsing returns bytes, not a JavaScript string. Use TextDecoder when text decoding is needed. The package documentation suggests @exodus/bytes as a TextDecoder polyfill when required.

import assert from "node:assert/strict";
import parseDataURL from "data-urls";

const result = parseDataURL("data:text/plain;charset=utf-8,Hello%20world");
assert.notEqual(result, null);
assert.equal(new TextDecoder().decode(result.body), "Hello world");

What this skill does not cover

This skill does not cover the internal WHATWG parsing algorithm, the complete MIMEType API, the complete whatwg-url URL-record API, runtime polyfill setup, or any CLI/tool workflow. The research describes no package-owned consumer CLI; the documented parser exports are used directly from a script.