Why introduce NPM package we can introduce direct use

Var bar = require(‘bar’) var bar = require(‘bar’)

We use the CommonJS modular specification directory structure

    --demo
        --node_module  // You can create folders manually
            --bar.js
        --demo.js
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bar.js

    var str = {
        str: 'I'm under node_module bar.js'
    }
    exports.str = str // Must be exported using modular standards
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demo.js

    var str = require('bar')  // The suffix can be omitted
    console.log(str)    // {STR: {STR: 'I am under node_module bar.js'}}
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The result of the data is {STR: {STR: ‘I am under node_module bar.js’}}

So when we use it, we need STR. STR is very unfriendly.

Let’s do it the other way

bar.js

    var str = {
        str: 'I'm under node_module bar.js'
    }
    module.exports = str // Must be exported using modular standards
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You can see some of the details of the introduction of modular exports

We can already implement it preliminarily if we change the directory structure

    --demo
        --node_module  // You can create folders manually
            --bar
                --bar.js
        --demo.js
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Do something about demo.js when you introduce it

    var str = require('bar/bar')  // The suffix can be omitted
    console.log(str)    // {STR: {STR: 'I am under node_module bar.js'}}
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That’s not what we’re looking for, either. The big step is coming

We will create a package.json file under the bar folder under node_module

NPM init -y creates the package.json file without prompting

{
  "name": "bar"."version": "1.0.0"."description": ""."main": "bar.js"."scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": []."author": ""."license": "ISC"
}
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Note that the main entry already specifies a folder

So we can do that when we use it

    var str = require('bar')  // The suffix can be omitted
    console.log(str)    // {STR: {STR: 'I am under node_module bar.js'}}
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