Merge prettierignore and gitignore

package.json

{
  "scripts": {
    "prettier:check": "./bin/prettier.sh --check",
    "prettier:fix": "./bin/prettier.sh --write",
  }
}

prettier.sh

#!/bin/bash

# There are files that we don't want prettier to format. 
# We define those in the .prettierignore file.
# 
# Furthermore, it doesn't make much sense to format files that are not tracked by git.
# In order to avoid repeating a list of files both in .gitignore and .prettierignore 
# this script will concat those two files and create a new temporaty file.
# 
# We do this becaude ATTOW the prettier --ignore-path flag only accepts one path

MODE_WRITE=--write
MODE_CHECK=--check

if [ "$1" = $MODE_WRITE ] || [ "$1" = $MODE_CHECK ]
then
  MODE=$1
  echo "Running format script with $MODE flag";

  IGNORE_TEMP_FILE='.temp-prettierignore'
  cat .prettierignore .gitignore > $IGNORE_TEMP_FILE

  prettier '**/*.{js,ts,tsx,md,json,scss,yml}' $MODE --ignore-path $IGNORE_TEMP_FILE; 

  rm $IGNORE_TEMP_FILE
else
  echo "Format not run. Need either $MODE_WRITE or $MODE_CHECK flag" >&2
fi