Testing Object.defineProperties using the Observer pattern. MDN shows that defaults for configurable, enumerable and writable are false. The implementation below is explicitly setting those values to false as a reminder.<\/p>\n
function MakeObservable(obj) {\n\n obj = obj || this;\n\n \/\/obj._observers = [];\n\n Object.defineProperties (obj, {\n\n _observers: {\n value: [],\n configurable: false,\n enumerable: false,\n writable : false\n },\n\n _watch: {\n value: function (name, observer, func) {\n if (!obj._observers.hasOwnProperty(name)) {\n obj._observers[name] = ({observer:observer, func:func});\n } else {\n console.log('This property already exists on this object');\n }\n\n },\n configurable: false,\n writable : false\n },\n \n _unwatch: {\n value: function (observer) {\n var idx = obj._observers.indexOf(observer);\n if (idx > -1) {\n obj.slice(idx, 1);\n }\n },\n configurable: false,\n writable : false\n },\n\n _updateWatcher: {\n value: function (observer) {\n console.log(\"Generic Notification from Watched Object\\n - Cannot Customize\");\n },\n configurable: false, \n writable : false\n },\n \n _updateWatchers: {\n value: function (prop, value) {\n var len = obj._observers.length;\n for (var prop in obj._observers) {\n \/\/ INTERNAL OBJECT NOTIFICATION\n \/\/obj._updateWatcher(obj._observers[watcher]);\n \/\/ GET WATCHER\n var watcher = obj._observers[prop];\n \/\/ CALL WATCHERS CUSTOM METHOD\n watcher.func(prop, value);\n };\n },\n },\n set: {\n value: function(prop, value) {\n obj[prop] = value;\n obj._updateWatchers(prop, value);\n }\n },\n get: {\n value: function(prop) {\n return obj[prop];\n }\n }\n });\n \n obj.set = function(prop, value) {\n obj[prop] = value;\n obj._updateWatchers(prop);\n\n };\n\n obj.get = function(prop) {\n return obj[prop];\n };\n\n return obj;\n}\n\nvar obj = new MakeObservable();\n\n\/\/ CREATE WATCHER\nvar watcher = {\n func: function(prop, value) {\n console.log(\"FIRST WATCHER\", prop, value);\n }\n};\n\n\/\/ ADD WATCHER NAME, WATCHER AND FUNCTION TO BE CALLED ON UPDATE\nobj._watch(\"watcher\", watcher, watcher.func);\n\n\/\/ TEST WATCHERS\nobj.set('name', 'First Name');\n\n\/\/ CREATE WATCHER\nvar watcher2 = { \n func: function(prop, value) { \n console.log(\"SECOND WATCHER\", prop, value); \n }\n};\n\n\/\/ ADD SECOND WATCHER NAME, WATCHER AND FUNCTION TO BE CALLED ON UPDATE\nobj._watch(\"watcher2\", watcher2, watcher2.func);\n\n\/\/ TEST WATCHERS\nobj.set('name', 'Second Name');\n<\/pre>\n","protected":false},"excerpt":{"rendered":"Testing Object.defineProperties using the Observer pattern. MDN shows that defaults for configurable, enumerable and writable are false. The implementation below is explicitly setting those values to false as a reminder. function MakeObservable(obj) { obj = obj || this; \/\/obj._observers = []; Object.defineProperties (obj, { _observers: { value: [], configurable: false, enumerable: false, writable : false […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-203","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/posts\/203","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=203"}],"version-history":[{"count":4,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/posts\/203\/revisions"}],"predecessor-version":[{"id":207,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=\/wp\/v2\/posts\/203\/revisions\/207"}],"wp:attachment":[{"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=203"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tech.shinynewthings.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}