Some Bash Functions

functions.sh

#!/bin/bash

function get_rand {
    echo "$(date +%s)"
}

function is_empty {
    if [[ -z "$1" ]]; then echo 1; else echo 0; fi
}

function is_array {
    local REF=$1
    local ARGUMENTS=""
    ARGUMENTS=$(declare -p ${REF} 2>/dev/null)
    if [[ ${ARGUMENTS} =~ "declare -a" ]]; then echo 1; else echo 0; fi
}

function is_assoc_array {
    local REF=$1
    local ARGUMENTS=""
    ARGUMENTS=$(declare -p ${REF} 2>/dev/null)
    if [[ ${ARGUMENTS} =~ "declare -A" ]]; then echo 1; else echo 0; fi
}

function array_total {
    local VALUES=$1
    IFS=' ' read -a ARRAY <<< "$VALUES"
    local TOTAL="${#ARRAY[@]}"
    echo "$TOTAL"
}

function array_last {
    local VALUES=$1
    IFS=' ' read -a ARRAY <<< "$VALUES"
    echo "${ARRAY[-1]}"
}

function array_pop {
    local VALUES=$1
    local LENGTH=$(array_total "$VALUES")
    IFS=' ' read -a ARRAY <<< "$VALUES"
    unset "ARRAY[$LENGTH-1]"
    VALUES="${ARRAY[@]}"
    echo "$VALUES"
}

function array_slice {
    local VALUES=$1
    local OFFSET=$2
    local LENGTH=$3
    IFS=' ' read -a ARRAY <<< "$VALUES"
    echo "${ARRAY[@]:$OFFSET:$LENGTH}"
}

function array_to_json {
    # Passing the -n option to local causes the parameter to be a nameref variable
    local -n ARRAY=$1
    local VALUES=${ARRAY[@]}
    local VALUE=""
    local JSON=""

    for VALUE in ${VALUES}; do
        VALUE=$(wrap_quotes "$VALUE")
        JSON="$VALUE,$JSON"
    done

    # The json must be a minimum number of characters to be valid
    # Do not remove trailing slashes if empty
    if [ ${#JSON} -ge 1 ]; then
        JSON=${JSON::-1}
    fi

    echo "[$JSON]"
}

function assoc_array_to_json {
    # Passing the -n option to local causes the parameter to be a nameref variable
    local -n ARRAY=$1
    local KEYS=${!ARRAY[@]}
    local KEY=""
    local VALUE=""
    local JSON=""
    local IS_ARRAY=0
    local IS_ASSOC_ARRAY=0

    for KEY in ${KEYS}; do
        VALUE="${ARRAY[$KEY]}"
        IS_EMPTY=$(is_empty "$VALUE")
        IS_ARRAY=$(is_array "$VALUE")
        IS_ASSOC_ARRAY=$(is_assoc_array "$VALUE")
        if [ "$IS_EMPTY" -eq 1 ]; then
            VALUE='""'
        elif [ "$IS_ARRAY" -eq 1 ]; then
            VALUE=$(array_to_json "$VALUE")
        elif [ "$IS_ASSOC_ARRAY" -eq 1 ]; then
            VALUE=$(assoc_array_to_json "$VALUE")
        else
            VALUE=$(wrap_quotes "$VALUE")
        fi
        KEY=$(wrap_quotes "$KEY")
        JSON="$KEY:$VALUE,$JSON"
    done

    # The json must be a minimum number of characters to be valid
    # Do not remove trailing slashes if empty
    if [ ${#JSON} -ge 1 ]; then
        JSON=${JSON::-1}
    fi

    echo "{$JSON}"
}

function wrap_quotes {
    echo $(printf '"%s"' "$1")
}

function trim_trailing_char {
    local CHAR=$1
    local STR=$2
    local PATTERN="s/$CHAR$//"
    echo "$STR" | sed "$PATTERN"
}

function trim_whitespace {
    local STR=$1
    echo "$STR" | awk '{$1=$1};1'
}

function search_replace {
    local STR=$1
    local SEARCH=$2
    local REPLACE=$3
    local PATTERN="s/$SEARCH/$REPLACE/g"
    echo "$STR" | sed "$PATTERN"
}

function get_json_value {
    local KEY=$1
    local JSON=$2

    # Find the key value pair that matches the provided key
    local PATTERN="$(wrap_quotes "$KEY"):.*?[^\\\]\""
    local MATCH=""
    MATCH=$(echo "$JSON" | grep -Po "$PATTERN")

    # Get the value from our key value pair
    IFS=":" read -r "$KEY" OUTPUT <<< "$MATCH"
    local VALUE="$OUTPUT"

    # Trim unwanted characters from our value
    VALUE=$(trim_whitespace "$VALUE")
    VALUE=$(trim_trailing_char ',' "$VALUE")
    VALUE=${VALUE:1:-1}

    echo "$VALUE"
}

function get_object_from_array {
    local INDEX=$1 # 0, 1, 2...
    local OBJECTS=$2 # [{"foo":"bar"},{"hello":"world"}]
    local OBJECT="" # {"foo":"bar"}
    local NEWLINE='\n\r'
    local DELIMITER="},{"
    local REPLACEMENT="}$NEWLINE{"
    # Removes the [ and ] characters from each side
    OBJECTS=$(trim_whitespace "$OBJECTS")
    OBJECTS=${OBJECTS:1:-1}
    # Remove whitespace from delimiter
    OBJECTS=$(search_replace "$OBJECTS" "},\s{" "$DELIMITER")
    # Splits the objects into new lines
    OBJECTS=$(search_replace "$OBJECTS" "$DELIMITER" "$REPLACEMENT")
    # Uses the internal field separator to parse each line into an array
    declare -a ARRAY
    readarray ARRAY <<< "$OBJECTS"
    # Returns the requested object by index
    OBJECT="${ARRAY[$INDEX]}"
    # Remove delimiter from output
    OBJECT=$(search_replace "$OBJECT" "$DELIMITER" "")
    echo "$OBJECT"
}

function join_by {
    IFS="$1"
    shift
    echo "$*"
}

function exit_on_error {
    local RESPONSE=$1
    local IS_ERROR=""
    local ERROR_MESSAGE=""
    IS_ERROR=$(get_json_value "error" "$RESPONSE")
    if [[ "$IS_ERROR" == "true" ]]; then
        ERROR_MESSAGE=$(get_json_value "message" "$RESPONSE")
        echo_red "Error: $ERROR_MESSAGE"
        export ERROR=1
    fi
}

function echo_red {
    local MSG=$1
    local COLOR='\033[0;31m'
    local N0_COLOR='\033[0m'
    local NEW_LINE='\n'
    printf "$COLOR$MSG$N0_COLOR$NEW_LINE"
}

function echo_green {
    local MSG=$1
    local COLOR='\033[0;32m'
    local N0_COLOR='\033[0m'
    local NEW_LINE='\n'
    printf "$COLOR$MSG$N0_COLOR$NEW_LINE"
}

function echo_yellow {
    local MSG=$1
    local COLOR='\033[1;33m'
    local N0_COLOR='\033[0m'
    local NEW_LINE='\n'
    printf "$COLOR$MSG$N0_COLOR$NEW_LINE"
}

function echo_grey {
    local MSG=$1
    local COLOR='\033[1;30m'
    local N0_COLOR='\033[0m'
    local NEW_LINE='\n'
    printf "$COLOR$MSG$N0_COLOR$NEW_LINE"
}