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1. resolve parameter of promise 1.1 common values or objects When the parameter of the resolve method is a normal value or object, the Promise state changes directly. new Promise((resolve, reject) => { // pending -> fulfilled // Resolve (basic data type or common object) resolve('promise'); // resolve({name: 'fct'}); }).then(res = ...

1, Create an object using object <script> // create object var stu = new Object() // Adding properties to an object stu.name='jibu' stu[9527] = 'jibu' //Special attribute names use square brackets // Adding methods to objects stu.study = function(){ console.log('study') ...

Scope 1. What is scope A scope is the accessibility of variables, functions, and objects in certain parts of the runtime code. In other words, the scope determines the visibility of variables and other resources in the code block. Maybe these two sentences are not easy to understand. Let's take a look at an example: function outFun2() { ...

brief introduction In large applications, some components may not be displayed at the beginning and will only be rendered under specific conditions. In this case, the resources of the component do not need to be loaded at the beginning, and can be requested when necessary. This can also reduce the resource volume loaded on the page for the fir ...

📖 preface In the front-end interview, inheritance is a common question, and the interviewer will always try his best to ask you. For example, what kinds of inheritance do you know? What is the difference between these inheritance methods? What are the advantages and disadvantages of these inheritance methods? What are the characteristic ...

Preliminary study on scaffold necessity It is convenient for multiple people to cooperate, and there is no need to build the initial project from scratch to improve the front-end R & D efficiency. What is scaffolding Scaffolding is essentially an operating system client, which executes commands, for example 🌰: vue create my-proje ...

Ice cone visualization Rectangular ice cone diagram d3.partition() official document Used to generate adjacency graph: a space filling variant of node link tree graph. Unlike using wires to link nodes and parent nodes, in this layout, nodes are drawn as an area (either arc or rectangle), and their position reflects their relative position in ...

Author: shade Translator: front end Xiaozhi Source: learnvue There are dreams and dry goods. Wechat search [Daqian world] pays attention to this bowl washing wisdom who is still washing dishes in the early morning. This article GitHub https://github.com/qq449245884/xiaozhi It has been included. There are complete test sites, materials a ...

A function is composed of a series of subroutines (a collection of statements), which can be called by external programs. After passing parameters to the function, the function can return a certain value. Note that the function in JavaScript is also an object. When you use typeof to check a function object, function will be returned. 4.1 d ...

Hello, my name is little bald monk This article is to explain how cloud development can upload, download, preview and delete images, and display the functions of images in a nine house grid 1. Realization effect Don't talk nonsense. Look at the effect first explain: In the middle of the pause, I was choosing to upload photos. Clic ...