webpack/hot/dev-server.js

Packs ECMAScript/CommonJs/AMD modules for the browser. Allows you to split your codebase into multiple bundles, which can be loaded on demand. Supports loaders to preprocess files, i.e. json, jsx, es7, css, less, ... and your custom stuff.

/*
	MIT License http://www.opensource.org/licenses/mit-license.php
	Author Tobias Koppers @sokra
*/
/* globals __webpack_hash__ */
if (module.hot) {
	/** @type {undefined|string} */
	var lastHash;
	var upToDate = function upToDate() {
		return /** @type {string} */ (lastHash).indexOf(__webpack_hash__) >= 0;
	};
	var log = require("./log");
	var check = function check() {
		module.hot
			.check(true)
			.then(function (updatedModules) {
				if (!updatedModules) {
					log(
						"warning",
						"[HMR] Cannot find update. " +
							(typeof window !== "undefined"
								? "Need to do a full reload!"
								: "Please reload manually!")
					);
					log(
						"warning",
						"[HMR] (Probably because of restarting the webpack-dev-server)"
					);
					if (typeof window !== "undefined") {
						window.location.reload();
					}
					return;
				}

				if (!upToDate()) {
					check();
				}

				require("./log-apply-result")(updatedModules, updatedModules);

				if (upToDate()) {
					log("info", "[HMR] App is up to date.");
				}
			})
			.catch(function (err) {
				var status = module.hot.status();
				if (["abort", "fail"].indexOf(status) >= 0) {
					log(
						"warning",
						"[HMR] Cannot apply update. " +
							(typeof window !== "undefined"
								? "Need to do a full reload!"
								: "Please reload manually!")
					);
					log("warning", "[HMR] " + log.formatError(err));
					if (typeof window !== "undefined") {
						window.location.reload();
					}
				} else {
					log("warning", "[HMR] Update failed: " + log.formatError(err));
				}
			});
	};
	var hotEmitter = require("./emitter");
	hotEmitter.on("webpackHotUpdate", function (currentHash) {
		lastHash = currentHash;
		if (!upToDate() && module.hot.status() === "idle") {
			log("info", "[HMR] Checking for updates on the server...");
			check();
		}
	});
	log("info", "[HMR] Waiting for update signal from WDS...");
} else {
	throw new Error("[HMR] Hot Module Replacement is disabled.");
}