modules

Node.js

# initializing metadata and dependencies file (package.json)
$ npm init
# installing a module
$ npm install moment --save
# updating a module
$ npm install moment@latest --save
# removing a module
$ npm uninstall moment --save
# pruning modules (removing unused modules)
$ npm prune
# publishing a module
$ npm publish

// importing a module
const moment = require('moment')
const now = moment().unix()
console.log(now)

Output

1546595748

// exporting a module
module.exports = {
  greet(name) {
    console.log(`hello ${name}`)
  }
}

// importing exported module
const greeter = require('./greeter')
greeter.greet('bob')

Output

hello bob

Go

Setup

# enable Go modules support
GO111MODULE=on
# initializing dependencies file (go.mod)
$ go mod init
# installing a module
$ go get github.com/go-shadow/moment
# updating a module
$ go get -u github.com/go-shadow/moment
# removing a module
$ rm -rf $GOPATH/pkg/mod/github.com/go-shadow/moment@v<tag>-<checksum>/
# pruning modules (removing unused modules from dependencies file)
$ go mod tidy
# download modules being used to local vendor directory (equivalent of downloading node_modules locally)
$ go mod vendor
# publishing a module:
# Note: Go doesn't have an index of repositories like NPM.
# Go modules are hosted as public git repositories.
# To publish, simply push to the repository and tag releases.

package main
import (
    "fmt"
    // importing a module
    "github.com/go-shadow/moment"
)
func main() {
    now := moment.New().Now().Unix()
    fmt.Println(now)
}

Output

1546595748

package greeter
import (
    "fmt"
)
// exporting a module (use a capitalized name to export function)
func Greet(name string) {
    fmt.Printf("hello %s", name)
}

package main
import (
    // importing exported module
    greeter "github.com/miguelmota/golang-for-nodejs-developers/examples/greeter_go"
)
func main() {
    greeter.Greet("bob")
}

Output

hello bob