Generate env-config.js based on .env file and ENVs variables. ENVs varibales overwrite .env

generate_env_config_file.sh

#!/bin/sh

# line endings must be \n, not \r\n !
# Writes JS code which opens object literal and assigns it to the global window object. 
# Reads each line of .env file and splits into key/value pair. 
# Looks for the environment variable, if set, uses its value, otherwise, uses the default value from .env file.
# Removes all carriage returns (\r) 
# Append it to object that we assigned to global window object. 
# Close object literal
echo "window.env = {" > ./env-config.js
awk -F '=' '{gsub (/ |\r$/, "")}{ print $1 ": \"" (ENVIRON[$1] ? ENVIRON[$1] : $2) "\"," }' ./.env >> ./env-config.js
echo "}" >> ./env-config.js