module.exports can export objects directly and reference them directly.
unlike Java, only class can be introduced.
then why do Node developers need to use class?
module.exports can export objects directly and reference them directly.
unlike Java, only class can be introduced.
then why do Node developers need to use class?
tell me about my own situation:
in actual production, it is almost not used. At present, it is mainly koa development
are all in the form of export function
because javascript is a language based on object prototypes, in fact, class is just a simulation of class effects, essentially an object.
are mainly some class libraries, with a high degree of reuse, and classes are the most appropriate. If you are on typescript or es6, you are basically writing classes
, to be honest, there are quite a lot, but js itself does not have a class, so you can understand it as a class, or to export a function.
such as sequelize and mongoose have many class concepts, for example, they usually inherit Error to implement their own Error class, but you say that is function , which is also true, or even more accurate. What can I say. Mainly by concept.
in fact, class is just grammatical sugar, which is written differently like the principle of es5, but is more inclined to the strong language type of java. There is not much difference between class and ordinary functions, so it encapsulates commonly used code. But personally, it is neat and readable to use class, which is convenient for other developers to use and understand
.In the scenario, the front end uploads the file to node api,api through xhr and calls the upload method put of Aliyun oss sdk (or multipart), Aliyun is responsible for uploading the file to oss.. Well, the problem is that when the front end monitors the...
through the goto to the download link, the exe file will be displayed, saved or discarded when the download is complete. how do I write code to save it automatically? ...
it feels like you can t manipulate json,. At most, it s an array. ...
after installing the extension of nunjucks, when you open the template file of nunjucks, you will be prompted that there is no formatter for the nunjucks file when you format the file. how to format the template file of nunjucks? ...
ask: v-for n child components in the parent component, and there is a value in the child component. Pass the value value $emit to the parent component. Why can the parent component only receive the value of the first child component, and why can t the...
shouldn t vue use vue-router? Why can it only be put into devDependencies (development dependency)? ...
for example, [ "1 ", "] I want to get the element in the array that is not ", that is, the return result is " 1 "....
question 1: why is the middleware in the koa2 framework written in the form of async, rarely in Synchronize mode (that is, without async)? For example, app.use(async (ctx, next) => { const start = new Date() await next() const ms = new Date() ...
A project of practicing hands. I want to climb the singer information on NetEase Cloud code is similar to . const request = require( superagent ); const cheerio = require( cheerio ); request .get( http: music.163.com -sharp discover artist ca...
recently, when I was writing a node project, I found that it was troublesome to write a bunch of sql statements when connecting to mysql with node.js. I went to npm s official website to search for nothing, so I would like to ask if there is a similar f...
how does react ant use custom form validation? 1. Code const Login = ( { loading, dispatch, form: { getFieldDecorator, validateFieldsAndScroll }, } ) => { function handleOk() { validateFieldsAndScroll((error...
Let the boss take a look. What I want to ask is, can I set the default style of the damaged image when img is empty? ...
ask for answers from all kinds of gods ...
simply write a project with ant-design-pro, and write a server.js and npm run build packaged file in the root directory with the built-in mock API,. The dist directory is as follows: server.js: server.js302Cannot read property notifyCount of unde...
the program node is currently not installed? here are the installation steps: enter the command: wget https: npm.taobao.org mirror. xz-d node-v8.9.3-linux-x64.tar.xz or tar-xzvf node-v8.9.3-linux-x64.tar.gz tar-xvf node-v8.9.3-linux-x64.tar ...
npm link npm WARN app@1.0.0 No repository field. up to date in 0.724s npm ERR! path C: Users Cooper AppData Roaming npm node_modules app app npm ERR! code ENOENT npm ERR! errno -4058 npm ERR! syscall chmod npm ERR! enoent ENOENT: no such file o...
the problem is this: when the foreground wants to modify, click modify, and then the background gives out the mod_data and then you can modify it. I know that the problem is probably the problem here with default. The first time I clicked on the banne...
prompt for an error when running npm install module.js:549 throw err; ^ Error: Cannot find module update-notifier at Function.Module._resolveFilename (module.js:547:15) at Function.Module._load (module.js:474:25) at Module.requ...
error installing Times $ yarn global add weex-toolkit yarn global v1.2.1 [1 4] Resolving packages... warning weex-toolkit > weex-builder > babel-preset-es2015@6.24.1: ? Thanks f or using Babel: we recommend using babel-preset-env now: please rea...
Today, when you look at the content of the node middleware section, it feels a lot like a filter, so is the so-called middleware another name for a filter? ...