goal

Use Node.js to display hello world on the console

Premise

Use Visual Studio Code (hereinafter VSCode) Use Node.js container with Docker

What is Node.js

--A mechanism that allows javascript, which is originally a client-side language, to be used on the server side (* 1) ――You can create various things such as websites, web applications, smartphone sites, games, etc. => Paypal, uver, etc. are also made with Node.js! ――We are good at processing a large amount of data, and the processing speed is fast.

1 Quoted from progate "What is Node.js" https://prog-8.com/nodejs/study/1/1#/2 Reference: https://udemy.benesse.co.jp/development/system/node-js.html

Download Node.js to Docker

Install Docker, a VScode extension, in advance. (* 2)

Create docker-compose.yml file

Create a Nodejs-sample-app (any folder name is fine) folder. Create a docker-compose.yml file under it. This is a standard file when downloading a container to docker, so the file name is fixed. A yml file is a text file written according to the YAML format, and is used for data transfer. This time, it is described as follows.

`docker-compose.yml`


version: "3"
services:
    node:
        image: node:14.15
        volumes:
            - .:/project
        tty: true
        working_dir: /project
        command: bash

Meaning of each item

2 This page is recommended for details. @Teach "Introduction to Docker with VS Code" https://qiita.com/Teach/items/ca09b8882f519dca600c

Download the image to doceker

Using the terminal function of VSCode, enter the Nodejs-sample-app folder and type the following command to download Node.js to docker.

docker-compose up -d

image スクリーンショット_2021-01-16_10_53_46.jpg

I opened docker and it looks like this!

Select Attach shell to enter the container (see photo) スクリーンショット_2021-01-16_12_33_56.jpg

You can switch between the local terminal and the container terminal here スクリーンショット_2021-01-16_12_38_45.jpg

Creating an app.js file

Create a app.js file in the same hierarchy as docker-compose.yml. This time it is described as follows

`app.js`


console.log("Hello nodejs");

At the terminal inside the container

`$ node app.js`


 When you type the command and the following is displayed, Node.js environment construction is complete!

 ![スクリーンショット_2021-01-16_12_47_28.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/663834/a2844d6f-68de-12c5-7c35-d6baf8f095fb.jpeg)

Hello world in node.js