react-svg-favicon

react-svg-favicon is a simple package for using dynamically generated "favicons" in your React app with the power of SVG. You just supply the SVG as regular React components and react-svg-favicon handles the rest.

Installation

npm install react-svg-favicon

Example usage

import { useState } from "react";
import SVGIcon from "react-svg-favicon";

export function App() {
  var [notifications, setNotifications] = useState(0);

  return (
    <>
      <button onClick={() => setNotifications((n) => n + 1)}>
        Add notification
      </button>

      <SVGIcon>
        <svg viewBox="0 0 100 100">
          <circle cx={50} cy={50} r={45} fill="orange" />
          <path
            d="M25 65 L40 50 L25 35 L35 25 L50 40 L65 25 L75 35 L60 50 L75 65 L65 75 L50 60 L35 75 Z"
            fill="black"
          />

          {notifications > 0 && (
            <>
              <circle cx={70} cy={70} r={30} fill="red" />
              <text
                x={70}
                y={85}
                fontSize={50}
                fontFamily="monospace"
                textAnchor="middle"
              >
                {notifications}
              </text>
            </>
          )}
        </svg>
      </SVGIcon>
    </>
  );
}

Caveats

In some browsers, the custom icon won't override static icons specified in the html template.

The SVGIcon component adds a new link[rel=icon] element at the very end of the document head. It also has a sizes="any" attribute by default.

The browser should always select the last icon specified, unless it considers another icon better based on the type, sizes, and media attributes.

Since "any" should match every size possible, the new icon should always win, which it does in Firefox. Chromium, however, doesn't follow the specification quite correctly.

To make it work in Chrome, you can either specify the same one numerical size or any for both the dynamic and static icon, like this:

<link rel="icon" type="image/x-icon" sizes="32x32" href="favicon.ico" />
<SVGIcon sizes="32x32">{/* Your code */}</SVGIcon>

or like this: ("any" is the default)

<link rel="icon" type="image/x-icon" sizes="any" href="favicon.ico" />
<SVGIcon>{/* Your code */}</SVGIcon>

Alternatively, you can remove all old icons uppon page load by adding this script to index.js:

for (var icon of document.querySelectorAll("link[rel=icon]")) {
  icon.parentElement.removeChild(icon);
}

This method is pretty much guaranteed to work.

API

The package provides a single export:

SVGIcon

This component renders its children to a link[rel=icon] element it appends to the document head.

In addition to the children property, it also accepts the type, sizes, and media attributes, which are passed to the link element.

Example with all attributes:

<SVGIcon sizes="32x32" type="image/svg+xml" media="print">
  <svg viewBox="0 0 100 100">
    <circle cx={50} cy={50} r={50} fill="red" />
  </svg>
</SVGIcon>