{"id":71803,"date":"2020-01-10T16:54:09","date_gmt":"2020-01-10T11:24:09","guid":{"rendered":"https:\/\/www.vskills.in\/certification\/tutorial\/?p=71803"},"modified":"2024-04-12T14:22:43","modified_gmt":"2024-04-12T08:52:43","slug":"rxjs-library","status":"publish","type":"page","link":"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/","title":{"rendered":"RxJS Library"},"content":{"rendered":"\n<p><a href=\"https:\/\/www.vskills.in\/certification\/tutorial\/angular-7-developer-tutorials\/\" target=\"_blank\" rel=\"noreferrer noopener\">Go back to Tutorial<\/a><\/p>\n\n\n<p>Reactive programming is an asynchronous programming paradigm concerned with data streams and the propagation of change (Wikipedia). RxJS (Reactive Extensions for JavaScript) is a library for reactive programming using observables that makes it easier to compose asynchronous or callback-based code (RxJS Docs).<\/p>\n<p>RxJS provides an implementation of the Observable type, which is needed until the type becomes part of the language and until browsers support it. The library also provides utility functions for creating and working with observables. These utility functions can be used for:<\/p>\n<ul>\n<li>Converting existing code for async operations into observables<\/li>\n<li>Iterating through the values in a stream<\/li>\n<li>Mapping values to different types<\/li>\n<li>Filtering streams<\/li>\n<li>Composing multiple streams<\/li>\n<\/ul>\n<p><strong>Observable creation functions<\/strong><\/p>\n<p>RxJS offers a number of functions that can be used to create new observables. These functions can simplify the process of creating observables from things such as events, timers, promises, and so on. For example:<\/p>\n<p><u>Create an observable from a promise<\/u><\/p>\n<p>import { fromPromise } from &#8216;rxjs&#8217;;<\/p>\n<p>\/\/ Create an Observable out of a promise<\/p>\n<p>const data = fromPromise(fetch(&#8216;\/api\/endpoint&#8217;));<\/p>\n<p>\/\/ Subscribe to begin listening for async result<\/p>\n<p>data.subscribe({<\/p>\n<p>next(response) { console.log(response); },<\/p>\n<p>error(err) { console.error(&#8216;Error: &#8216; + err); },<\/p>\n<p>complete() { console.log(&#8216;Completed&#8217;); }<\/p>\n<p>});<\/p>\n<p><u>Create an observable from a counter<\/u><\/p>\n<p>import { interval } from &#8216;rxjs&#8217;;<\/p>\n<p>\/\/ Create an Observable that will publish a value on an interval<\/p>\n<p>const secondsCounter = interval(1000);<\/p>\n<p>\/\/ Subscribe to begin publishing values<\/p>\n<p>secondsCounter.subscribe(n =&gt;<\/p>\n<p>console.log(`It&#8217;s been ${n} seconds since subscribing!`));<\/p>\n<p><u>Create an observable from an event<\/u><\/p>\n<p>import { fromEvent } from &#8216;rxjs&#8217;;<\/p>\n<p>const el = document.getElementById(&#8216;my-element&#8217;);<\/p>\n<p>\/\/ Create an Observable that will publish mouse movements<\/p>\n<p>const mouseMoves = fromEvent(el, &#8216;mousemove&#8217;);<\/p>\n<p>\/\/ Subscribe to start listening for mouse-move events<\/p>\n<p>const subscription = mouseMoves.subscribe((evt: MouseEvent) =&gt; {<\/p>\n<p>\/\/ Log coords of mouse movements<\/p>\n<p>console.log(`Coords: ${evt.clientX} X ${evt.clientY}`);<\/p>\n<p>\/\/ When the mouse is over the upper-left of the screen,<\/p>\n<p>\/\/ unsubscribe to stop listening for mouse movements<\/p>\n<p>if (evt.clientX &lt; 40 &amp;&amp; evt.clientY &lt; 40) {<\/p>\n<p>subscription.unsubscribe();<\/p>\n<p>}<\/p>\n<p>});<\/p>\n<p><u>Create an observable that creates an AJAX request<\/u><\/p>\n<p>import { ajax } from &#8216;rxjs\/ajax&#8217;;<\/p>\n<p>\/\/ Create an Observable that will create an AJAX request<\/p>\n<p>const apiData = ajax(&#8216;\/api\/data&#8217;);<\/p>\n<p>\/\/ Subscribe to create the request<\/p>\n<p>apiData.subscribe(res =&gt; console.log(res.status, res.response));<\/p>\n\n\n<p><a href=\"https:\/\/www.vskills.in\/certification\/tutorial\/angular-7-developer-tutorials\/\" target=\"_blank\" rel=\"noreferrer noopener\">Go back to Tutorial<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Go back to Tutorial Reactive programming is an asynchronous programming paradigm concerned with data streams and the propagation of change (Wikipedia). RxJS (Reactive Extensions for JavaScript) is a library for reactive programming using observables that makes it easier to compose asynchronous or callback-based code (RxJS Docs). RxJS provides an implementation of the Observable type, which&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"categories":[8294],"tags":[8366],"class_list":["post-71803","page","type-page","status-publish","hentry","category-angular-7","tag-rxjs-library"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v24.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>RxJS Library - Tutorial<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"RxJS Library - Tutorial\" \/>\n<meta property=\"og:description\" content=\"Go back to Tutorial Reactive programming is an asynchronous programming paradigm concerned with data streams and the propagation of change (Wikipedia). 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RxJS provides an implementation of the Observable type, which...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/\" \/>\n<meta property=\"og:site_name\" content=\"Tutorial\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/vskills.in\/\" \/>\n<meta property=\"article:modified_time\" content=\"2024-04-12T08:52:43+00:00\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/\",\"url\":\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/\",\"name\":\"RxJS Library - Tutorial\",\"isPartOf\":{\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#website\"},\"datePublished\":\"2020-01-10T11:24:09+00:00\",\"dateModified\":\"2024-04-12T08:52:43+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/www.vskills.in\/certification\/tutorial\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"RxJS Library\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#website\",\"url\":\"https:\/\/www.vskills.in\/certification\/tutorial\/\",\"name\":\"Tutorial\",\"description\":\"Vskills - A initiative in elearning and certification\",\"publisher\":{\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/www.vskills.in\/certification\/tutorial\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#organization\",\"name\":\"Vskills\",\"url\":\"https:\/\/www.vskills.in\/certification\/tutorial\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/www.vskills.in\/certification\/tutorial\/wp-content\/uploads\/2017\/07\/vskills-min-logo.jpg\",\"contentUrl\":\"https:\/\/www.vskills.in\/certification\/tutorial\/wp-content\/uploads\/2017\/07\/vskills-min-logo.jpg\",\"width\":73,\"height\":55,\"caption\":\"Vskills\"},\"image\":{\"@id\":\"https:\/\/www.vskills.in\/certification\/tutorial\/#\/schema\/logo\/image\/\"},\"sameAs\":[\"https:\/\/www.facebook.com\/vskills.in\/\",\"https:\/\/x.com\/vskills_in\",\"https:\/\/www.linkedin.com\/company-beta\/1371554\/\",\"https:\/\/www.youtube.com\/channel\/UCMWnscxPwRF_PqXo9B7q_Tw\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"RxJS Library - Tutorial","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.vskills.in\/certification\/tutorial\/rxjs-library\/","og_locale":"en_US","og_type":"article","og_title":"RxJS Library - Tutorial","og_description":"Go back to Tutorial Reactive programming is an asynchronous programming paradigm concerned with data streams and the propagation of change (Wikipedia). 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