node/.devcontainer/devcontainer.json

{
    "name": "Node.js Sample",
    "dockerFile": "Dockerfile",

    // Use 'appPort' to create a container with published ports. If the port isn't working, be sure
    // your server accepts connections from all interfaces (0.0.0.0 or '*'), not just localhost.
    "appPort": [3000],

    // Comment out the next line to run as root instead.
    "remoteUser": "node",

    // Use 'settings' to set *default* container specific settings.json values on container create. 
    // You can edit these settings after create using File > Preferences > Settings > Remote.
    "settings": {
        "terminal.integrated.shell.linux": "/bin/bash"
    },

    // Specifies a command that should be run after the container has been created.
    "postCreateCommand": "yarn install",
    "initializeCommand": "echo INIT called",
    // Add the IDs of extensions you want installed when the container is created in the array below.
    "extensions": [
        "dbaeumer.vscode-eslint"
    ]
}