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The example of how to render something only on client side

Inspired by facebook/react#10923 (comment)

class OnlyOnClient extends Component {
  static propTypes = {
    placeholder: PropTypes.node,
    html: PropTypes.string
  };

 state = {

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// fork.js
const { fork } = require('child_process');

const getMessage = () =>
  new Promise((resolve, reject) => {
    fork('src/child')
      .on('message', message => {
        resolve(message);
 })

EddiG

How to use Docker

As Node.js powered development environment

Initialize new container with name my_project

docker run -it -d -v "$(PWD)":/app -v /app/node_modules -w /app -p 8080:8080 --name my_project node:8 /bin/bash

Notice how we mount new volume above node_modules folder. In this way, we significantly improve performance for host machines powered by OSX or Windows. Otherwise, we will stay with a poor native performance when the Docker synchronize file system state on host and container on npm install command execution.

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Python 3

Discovery helpers

Getting a description about some of the classes or functions

help(tuple)
help(tuple.count)

Getting attributes of object

dir(tuple)

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image = 'node:8.9.3'
container = 'my-project'
volume = 'my-project-volume'
site_port = '8080:8080'

build:
	docker run -it -d -v '$(CURDIR)':/app -v ${volume}:/app/node_modules -w /app -p $(site_port) --name $(container) $(image) /bin/bash
	docker exec -it $(container) yarn install

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const DeleteItemMutation = ({ id, render }) => (
  <Mutation mutation={DELETE_ITEM_MUTATION}>
    {mutate =>
      render({
        deleteItem: id => {
          mutate({
            variables: { id },
            // optimisticResponse
 // update

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Running Elasticsearch on Amazon Machine Image (AMI)

1. Install the Elasticsearch following this instruction
2. Install Java sudo yum install java-1.8.0-openjdk
3. Choose the installed Java version sudo /usr/sbin/alternatives --config java
4. Install Amazon specific plugin sudo /usr/share/elasticsearch/bin/elasticsearch-plugin install discovery-ec2
5. Edit configurations in /etc/elasticsearch/
6. Run the Elasticsearch sudo -i service elasticsearch start
7. Look at the logs if didn't start /var/logs/elasticsearch/
8. Add to autostart on reboot sudo chkconfig elasticsearch on (for verifying sudo chkconfig --list)

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Was taken from https://github.com/kentcdodds/testing-workshop/tree/master/other/configuration/calculator.solution

package.json

{
  "babel": {
    "presets": "./.babelrc.js"
  }
}

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Creating case sensitive/insensitive volumes (https://www.dssw.co.uk/reference/diskutil.html)

# For case insensitive
diskutil apfs addVolume disk1 APFS <Volume name>
# For case sensitive
diskutil apfs addVolume disk1 "Case-sensitive APFS" <Volume name>

The newly created volume will be mounted to the /Volume/

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Find all GraphQL queries/mutations in the directory

grep -Pzo 'gql`\s+(query|mutation)[\s\S]+?`' src/* -R | less

The output will be something like this

src/components/CurrentUser.js:gql`
  query CurrentUser {
    user {
 id