parse_day_one_json.rb

#!/bin/env ruby
require 'json'
require 'time'

cutoff = Time.parse('2016-08-10')

log = JSON.load(ARGF)

entries_per_day = Hash.new{ |hash, key| hash[key] = [] }

(log['entries'].
	select { |e| Time.parse(e['creationDate']) > cutoff }.
	reverse.
	reduce (entries_per_day) { |memo, e| memo[Time.parse(e['creationDate']).strftime('%F')] << e; memo }).
	each_pair { |date, entries| 
		puts
		puts date
		entries.
			sort { |x, y| Time.parse(x['creationDate']) <=> Time.parse(y['creationDate']) }.
			each { |e| puts Time.parse(e['creationDate']).strftime('%R') + ' ' + e['text']}
	}

Simple script that will print out entries from Day One JSON dump.

Sample output:

2016-08-12
21:58 text
21:58 another