combine_json_files

#!/bin/bash

# This script combines .json files
#
# Usage: <scipt name> directory
#
# Input
# 	directory: a directory with .json files
#
# Output: .json file in the stdout 

set -e
set -u
set -o pipefail

# Read input arguments
declare directory="${1}"

main() {
	# Handle I/O
	local -a files=()
	readarray -d '' files < <(collect_json_files "${directory}")
	
	# Perfom computation and output
	combine_json_files_into_list 'files'
}

combine_json_files_into_list() {
	local file_list_name="${1}"
        local -n file_list="${1}"

	echo "["

	print_comma_seperated_content_of_json_files "${file_list_name}"

	echo "]"
}

print_comma_seperated_content_of_json_files() {
        local -n file_list="${1}"

	for f in "${file_list[@]:0:${#file_list[@]}-1}"; do
		cat "${f}" | sed '$s/$/,/'
	done

	if [ "${#file_list[@]}" -gt 0 ]; then
		cat "${file_list[-1]}" | sed '$s/$//'
	fi
}

collect_json_files() {
	local directory="${1}"

	if [ ! -d "${directory}" ]; then
		return
	fi

	find "${directory}" -maxdepth 1 -mindepth 1 -type f -print0 \
		| sort -z \
		| grep -zIE '^*.\.json$'
}

main

exit 0