随笔分类 - Javascript
摘要：In normal Javascript, we do undefine check or null check: Sometime backend data return may contain or not contain 'name' prop. So let's see how to def
阅读全文
摘要：Well, this stuff will be a little bit strange if you deal with it first time. Container Object: Just a wrapper / contianer for values No Method No Nou
阅读全文
摘要：Let's learn how to unit test your JavaScript with Jest, a JavaScript unit testing framework from Facebook. We'll install and optimize Jest for this pr
阅读全文
摘要：Canvas is great for high performance graphics rendering but by default the results look blocky on phones tablets and laptops with high pixel density o
阅读全文
摘要：Learn how to use the new Webpack Dashboard from Formidable Labs to display a pretty, useful output for monitoring the status of your webpack builds. T
阅读全文
摘要：Not only can you provide default values when using ES6 parameter object destructuring, but you can also require the presence of certain properties. No
阅读全文
摘要：Often buttons need to be handled by JavaScript, and if done improperly it can lead to accessibility issues. In this lesson you will improve a major ne
阅读全文
摘要：let person = { firstName: "Zhentian", lastName: "Wan" }; /*Object.freeze() makes object cannot be updated, added or deleted*/ let freezePerson = Object.freeze(person); freezePerson.address="Finl...
阅读全文
摘要：Use map() and Number() to convert to number if possilbe or NaN.
阅读全文
摘要：In this lesson we look at using color and the basic drawing methods of p5js, and how they can be combined to create a simple graphic on the canvas.
阅读全文
摘要：If you’re only instrumenting the files in your project that are under test then your code coverage report will be misleading and it will be difficult
阅读全文
摘要：How much of your code runs during unit testing is an extremely valuable metric to track. Utilizing code the karma-coverage plugin and babel-plugin-__c
阅读全文
摘要：When writing tests run by Karma for an application that’s bundled with webpack, it’s easiest to integrate webpack and Karma directly together. In this
阅读全文
摘要：When you have a dependency that has dependencies on global variables (like jQuery or lodash) or assumes that this is bound to window, you can use the
阅读全文
摘要：Let's try creating a deeper tree structure. This time we have 4 separate arrays each containing lists, videos, boxarts, and bookmarks respectively. Ea
阅读全文
摘要：1. Use a for loop to traverse the videos and bookmarks array at the same time. For each video and bookmark pair, create a {videoId, bookmarkId} pair a
阅读全文
摘要：Three ways to make object immutable: 1. Use JSON.parse(JSON.stringify(obj)): this approach is little bit expense. 2. Use Object.create() This is a che
阅读全文
摘要：concatAll: Exercise 12: Retrieve id, title, and a 150x200 box art url for every video You've managed to flatten a tree that's two levels deep, let's t
阅读全文
摘要：fetch() does the same thing as XHR, but fetch return a promise. Check the reponse API here: Link Besides text(), you can use json() or blob(). 'no-cor
阅读全文
摘要：You can fine tune several webpack plugins to make your bundle as small as it can be for your specific application. However there are a few things you
阅读全文
浙公网安备 33010602011771号