Explain four interesting NPM usages with charts

1、 npm add to === npm install

If you try to npm Search in official documents npm add command , You will find that this command doesn't seem to exist at all , Here's the picture ：

But we can use this command on the terminal ：

$ npm add lodash

actually ,npm add yes npm install One of the aliases of . So when we use npm add when , Exactly equivalent to npm perform npm install ！

Again ,npm i It's also npm install Another name for .

2、npm instal ?  No problem

Careful readers may have found out , The installation in the subtitle above is a misspelling of this word . But it does work .

$ npm instal lodash

Actually, this is npm 8.x A new feature of version , It's called fault tolerant design . If the user accidentally misspells a word ,NPM It still works .

So in 8.x In the version ,npm install Got it 9 An alias , Namely ：

in, ins, inst, insta, instal, isnt, isnta, isntal, isntall

3、 You can perform some additional actions before and after each script execution

Suppose we have a name greet Script for ：

Now we want to ：

• stay greet Output something before execution ： stay greet Before doing something ;

• stay greet Output something after execution ： stay greet Then do something .

So what should we do ？

We can add a pregreet Script and a postgreet Script , This is a NPM The mechanism of , With pre and post The first script is considered a special script .

This mechanism is often used in the automatic deployment of projects .

4、 Use npm link Install some terminal commands

If you are in the project package.json In the definition of bin Property and point it to the executable script file .

for example ：

package.json :

{
     "name": "npm-test",  "bin": {
       "hello-npm-1": "./build/hello.sh"  }}

hello.sh :

echo "hello npm"

And then we can use it npm link Install it to shell In command ：

In the figure ：

This is how to install create-react-app and vue-cli The way .