A shell function that removes a key from a JSON file

README.md

Readme

Important:

I wrote this function to manipulate my package.json.
This is a suboptimal solution; the correct way is via the official npm-pkg.

Authors

@nicholaswmin

License

MIT

delete-json-key.sh

#!/usr/bin/env

#######################################
# deleteJSONKey() $key $json_file_path
#
# Deletes a property from a JSON file,
# taking care of dangling commas if needed
#
# Usage example:
#
# deleteJSONKey "version" package.json
#
# Removes the "version" property
# of file "package.json""
#
# Note:
# - Only the 1st match is removed.
# - To remove multiple instances of the same key,
#  call it multiple times.
#
# Globals:
#
# - none
#
# Arguments:
#
# - key : the JSON key/property name to remove
# - file: the JSON file path
#
# Returns:
#
# - 0 if key was deleted
# - 1 otherwise
#
# License: MIT
# Authors: @nicholaswmin
#######################################

deleteJSONKey () {
  local key=$1
  local file=$2

  # verify params

  if ! [[ "${key}" ]]; then
    echo "- Missing \"key\" parameter"
    return 1
  fi

  if ! [[ "${file}" ]]; then
    echo "- Missing \"file\" parameter"
    return 1
  fi

  if [[ ! -f "${file}" ]]; then
    echo "- File: $file does not exist"
    return 1
  fi

  local count=$(grep -n "${key}" "${file}" | wc -l)
  local line_num=$(grep -n "${key}" "${file}" | head -1 | grep -Eo '^[^:]+')

  if [[ -z "$line_num" ]]; then
    echo "- Cannot find key: \"${1}\" in: ${file}"
    return 1
  fi

  # we also need the previous line in case it has
  # a dangling comma
  local line=$(sed -n "${line_num}"p "${file}")
  local prev_line_num=$((line_num - 1))
  local prev_line=$(sed -n "${prev_line_num}"p "${file}")

  # remove dangling comma of previous line,
  # if we need to.
  if ! [[ "${line: -1}" =~ ^[,]$ ]]; then
    if [[ -n "$prev_line" ]] && [[ "${prev_line: -1}" =~ ^[,]$ ]]; then
      sed -i "" $prev_line_num's/,//g' ${file}
    fi
  fi

  sed -i "" "${line_num}d" "${file}"

  echo "removed: 1, line number: ${line_num}, remaining: $((--count))"

  return 0
}

Follows: Google Shell Style Guide,