use-browser

A hook giving components the ability to render one markup on the server, then hydrate using that markup on the client and once hydrated swap that markup to the client markup.

This solves the issue of ReactDOM hydrate having issues with hydrating server markup with the client DOM by first letting the components render the server markup during hydration and then make them update to the client markup once hydration has finished.

Installation

npm i -E @crossroads-loyalty-solutions/react-use-browser

rollup-plugin-node-resolve needs to be told to load the browser-main when it is building the browser bundle:

import { resolvePlugin } from "rollup-plugin-node-resolve";

export default [
  {
    input: "src/server.js",
    plugins: [
      // ...
      resolvePlugin({
        preferBuiltins: true,
        mainFields: ["module", "main"],
      }),
      // ...
    ],
  },
  {
    input: "src/client.js",
    plugins: [
      // ...
      resolvePlugin({
        preferBuiltins: false,
        // Note the extra "browser" main-field:
        mainFields: ["browser", "module", "main"],
      }),
      // ...
    ],
  },
];

Usage

// app.js

import { useBrowser } from "@crossroads-loyalty-solutions/react-use-browser";

export const App = () => {
  const browser = useBrowser();

  if (browser) {
    return <p>This is browser markup</p>;
  }

  return <p>Server markup</p>;
};

// server.js

import { renderToString } from "react-dom/server";
import { App } from "./app";

res.write(`...
<div id="app">`, "utf-8");
res.write(renderToString(<App />), "utf-8");
res.write(`</div>
...`, "utf-8");

// client.js

import { hydrate } from "react-dom";
import { markHydrated } from "@crossroads-loyalty-solutions/react-use-browser";
import { App } from "./app";

const root = document.getElementById("app");

if (!root) {
  throw new Error("Missing app root");
}

hydrate(<App />, root, markHydrated);

API

useBrowser(): boolean

A hook returning true if the component is running in the browser. It will return false on the server and during client-hydration.

After client-hydration it will queue a re-render with the next render returning true.

markHydrated(): void

markHydrated should be called once hydration is finished on the client to flag that any uses of useHydrate should start with the client markup immeidiately.

If this function is not called once hydration is finished on the client then useBrowser will always perform a double-render as if it was hydrating in every new component using it, first with server-markup and then with client markup. Using markHydrated ensures that the client always renders client-markup right away from that point on.

This function will throw on the server.