yall.js is a featured-packed SEO-friendly lazy loader for img, picture, video and iframe elements, as well as CSS background images. It works in all modern browsers, including IE 11. It uses Intersection Observer where available, but as of version 3, this API must be polyfilled for older browsers. It can also monitor the DOM for changes using Mutation Observer to lazy load elements that have been appended to the DOM after initial load, which may be desirable for single page applications. It can also optimize use of browser idle time using requestIdleCallback, and reduce jank by using requestAnimationFrame.
Highly performant, light 1kb and configurable lazy loader in pure JS with no dependencies for responsive images, iframes and more. It is written with an aim to lazy load images, iframes, ads, videos or any other element using the recently added Intersection Observer API with tremendous performance benefits. Existing lazy loading libraries hook up to the scroll event or use a periodic timer and call getBoundingClientRect on elements that need to be lazy loaded. This approach, however, is painfully slow as each call to getBoundingClientRect forces the browser to re-layout the entire page and will introduce considerable jank to your website. Making this more efficient and performant is what IntersectionObserver is designed for, and it’s landed in Chrome 51. IntersectionObservers let you know when an observed element enters or exits the browser’s viewport.
React lazy load images with IntersectionObserver API and Priority Hints.
Lazy load images using Intersection Observer, apply progressive rendering and css animations. A Vue.js component to lazy load an image automatically when it enters the viewport using the Intersection Observer API.
Asynchronous boundary detection – lazy-loading, infinite scroll, and more. Whether you’re lazy-loading images, implementing infinite-scroll, or avoiding an ex-lover. it’s important to set boundaries. Historically, boundary detection required a mix of event handlers, loops, and calls to getBoundingClientRect. Since these operations run on the main thread, performance would suffer. Bounds.js defies these expectations, providing a simple and powerful API. It detects intersections between elements asynchronously, keeping complex operations off the main thread and improving performance.
ng-in-viewport gives you a directive that uses Intersection Observer API. To provides a simple way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document’s viewport.
A library to lazy load images using Intersection Observer.
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Memoization is a big complicated word that you may have never even heard before, but you may be surprised to know that you are most likely already using memoization without even realizing it. Memoization is just the act of caching values so that they can be calculated quicker in the future. Memoization is really useful in all parts of programming, but where it is most useful is in dynamic programming. In this video I will explain what memoization is, how to use it, and why it is so useful especially in dynamic programming.
🧠 Concepts Covered:
01 | Introduction
Get an introduction from Bob, as he kicks off the course, sets expectations, and gives you a little guidance for the road ahead.
02 | Setting Up the Development Environment
04 | Variables
Learn what variables are and how to declare, initialize, set, and get values from them.
05 | Data Types
06 | Type Coercion and Conversion
07 | Expressions and Operators
Learn how to spot a well-formed expression and how to compose expressions through the combination of operators and operands.
08 | Arrays
Watch as Bob demonstrates how to use arrays, how to add/remove elements of an array, how to access elements of an array using the index, how to get the number of elements in an array, and more.
09 | Function Declaration
Get an introduction to functions, as Bob shows you one way to define a function, how to call the function, how to pass parameters into a function, how to return values from a function, and more.
10 | Function Expressions
Sometimes a function declaration is more than you need. Get details in this lesson, as Bob demonstrates how to use a function expression and how to create an immediately invoked function expression.
11 | Decision Statements
Learn how to add logic to your applications by testing conditions using if / else statements, switch / case statements, and the ternary operator.
12 | Iteration Statements
Watch as Bob introduces the For and While statements, which enable you to loop through lists of values and perform operations on them.
13 | Basics of Scope
Hear an explanation of the notion of the lifetime of variables and their reach into other code blocks, in this discussion of scope.
14 | Returning Functions from Functions
15 | Object Literals
Objects contain properties and functions that describe attributes of the object and its behavior, respectively. Watch as Bob demonstrates how to create object literals.
16 | Module Pattern and Revealing Module Pattern
Learn how to introduce variables and functions without leaving an unnecessarily large footprint on the global scope.
17 | Closures
Closures allow developers to bind functions to their execution context, including variables, so you can build specialized versions of functions. Learn how closures work and how to create them.
18 | this Keyword
19 | Destructuring
20 | String Template Literals
Learn about the new string template literal syntax to enable string interpolation, multi-line string formatting, and more.
21 | Regular Expressions
Working with string data, Bob explains how use regular expressions to determine such things as whether a string matches a specific pattern or whether an instance of the pattern exists in a string.
22 | Built-In Natives
23 | Constructor Function Calls with the new Keyword
Learn how constructor functions work, see how to make key distinctions in what they are, and find out why they’re helpful.
24 | Objects and the Prototype Chain
26 | Arrow Functions
27 | Truthy and Falsy Values
28 | null Type
Similar to the undefined primitive type, the null type represents a variable that has no reference to an object when one was expected. Hear an explanation of how and why we should think about nulls.
29 | Date Objects
30 | String Methods
The built-in native String function provides several very useful methods for manipulating and evaluating strings. Watch Bob demonstrate how to use a few of the most useful ones.
31 | Array Methods
We’ve worked with arrays throughout this course. Now Bob takes a few minutes to show you some of the most useful methods provided by the Array built-in native function.
32 | Error Handling with Try Catch
See how to wrap a try/catch/finally statement around potentially problematic code to anticipate everything that could go wrong with it, and learn other error-handling tips.
33 | Understanding the Document Object Model
Watch Bob examine the web browser environment and how it creates an object graph of nodes that represent elements, their attributes, and text, plus how to properly attach your code to an HTML page.
34 | Working with DOM Nodes
Continuing from the previous video, Bob demonstrates a slightly more compelling example that helps us understand how to manipulate, create, and delete element nodes and attribute nodes.
35 | Course Conclusion
In this final video, Bob briefly adds some closing comments and well wishes. You can also optionally complete a survey to provide insight into how Microsoft can improve this course.
Thanks for watching ❤
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