Generating data URLs in JavaScript

All data URLs (also known as data URIs) begin with data:, followed by the media type string (which can be omitted) and the data itself.

Below are some examples of data URLs and ways to generate them.

text/plain data

const data = 'Hello World!'
console.log(`data:text/plain;charset=utf-8,${encodeURIComponent(data)}`)

text/plain data, base64 encoding

const data = 'Hello World!'
console.log(`data:text/plain;charset=utf-8;base64,${btoa(unescape(encodeURIComponent(data)))}`) // Browser
console.log(`data:text/plain;charset=utf-8;base64,${Buffer.from(data).toString('base64')}`) // Node.js

text/html data, base64 encoding

const data = '<b>Hello World!</b>'
console.log(`data:text/html;charset=utf-8;base64,${btoa(unescape(encodeURIComponent(data)))}`) // Browser
console.log(`data:text/html;charset=utf-8;base64,${Buffer.from(data).toString('base64')}`) // Node.js

image/svg+xml data, base64 encoding

const data =
  `<?xml version="1.0"?>
  <svg xmlns="http://www.w3.org/2000/svg" height="100" width="100">
    <circle cx="50" cy="50" r="20" fill="yellow" />
  </svg>`
console.log(`data:image/svg+xml;charset=utf-8;base64,${btoa(unescape(encodeURIComponent(data)))}`) // Browser
console.log(`data:image/svg+xml;charset=utf-8;base64,${Buffer.from(data).toString('base64')}`) // Node.js