webpack/hot/signal.js

Packs CommonJs/AMD modules for the browser. Allows to split your codebase into multiple bundles, which can be loaded on demand. Support 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 __resourceQuery */
if (module.hot) {
	var log = require("./log");
	var checkForUpdate = function checkForUpdate(fromUpdate) {
		module.hot
			.check()
			.then(function (updatedModules) {
				if (!updatedModules) {
					if (fromUpdate) log("info", "[HMR] Update applied.");
					else log("warning", "[HMR] Cannot find update.");
					return;
				}

				return module.hot
					.apply({
						ignoreUnaccepted: true,
						onUnaccepted: function (data) {
							log(
								"warning",
								"Ignored an update to unaccepted module " +
									data.chain.join(" -> ")
							);
						}
					})
					.then(function (renewedModules) {
						require("./log-apply-result")(updatedModules, renewedModules);

						checkForUpdate(true);
						return null;
					});
			})
			.catch(function (err) {
				var status = module.hot.status();
				if (["abort", "fail"].indexOf(status) >= 0) {
					log("warning", "[HMR] Cannot apply update.");
					log("warning", "[HMR] " + log.formatError(err));
					log("warning", "[HMR] You need to restart the application!");
				} else {
					log("warning", "[HMR] Update failed: " + (err.stack || err.message));
				}
			});
	};

	process.on(__resourceQuery.substr(1) || "SIGUSR2", function () {
		if (module.hot.status() !== "idle") {
			log(
				"warning",
				"[HMR] Got signal but currently in " + module.hot.status() + " state."
			);
			log("warning", "[HMR] Need to be in idle state to start hot update.");
			return;
		}

		checkForUpdate();
	});
} else {
	throw new Error("[HMR] Hot Module Replacement is disabled.");
}