init the awkward code

static/html/jspaint/src/storage.js

@@ -0,0 +1,73 @@
+// @TODO: remove remaining cruft from being compiled from CoffeeScript
+// or maybe replace this module with localforage actually
+// (but need to address asynchronous concerns if doing that)
+
+((exports) => {
+	let localStore = {
+		get(key, callback) {
+			let i, item, len, obj, keys, keys_obj;
+			try {
+				if (typeof key === "string") {
+					item = localStorage.getItem(key);
+					if (item) {
+						obj = JSON.parse(item);
+					}
+				} else {
+					obj = {};
+					if (Array.isArray(key)) {
+						keys = key;
+						for (i = 0, len = keys.length; i < len; i++) {
+							key = keys[i];
+							item = localStorage.getItem(key);
+							if (item) {
+								obj[key] = JSON.parse(item);
+							}
+						}
+					} else {
+						keys_obj = key;
+						for (key in keys_obj) {
+							let defaultValue = keys_obj[key];
+							item = localStorage.getItem(key);
+							if (item) {
+								obj[key] = JSON.parse(item);
+							} else {
+								obj[key] = defaultValue;
+							}
+						}
+					}
+				}
+			} catch (error) {
+				callback(error);
+				return;
+			}
+			callback(null, obj);
+		},
+		set(key, value, callback) {
+			let to_set = {};
+			if (typeof key === "string") {
+				to_set = {
+					[key]: value
+				};
+			} else if (Array.isArray(key)) {
+				throw new TypeError("Cannot set an array of keys (to what?)");
+			} else {
+				to_set = key;
+				callback = value;
+			}
+			for (key in to_set) {
+				value = to_set[key];
+				try {
+					localStorage.setItem(key, JSON.stringify(value));
+				} catch (error) {
+					error.quotaExceeded = error.code === 22 || error.name === "NS_ERROR_DOM_QUOTA_REACHED" || error.number === -2147024882;
+					callback(error);
+					return;
+				}
+			}
+			return callback(null);
+		}
+	};
+
+	exports.storage = localStore;
+
+})(window);