comparer 0.3.0

A simple library to track changes in a HashMap/DashMap over several iterations.

This library is designed to detect if a HashMap/DashMap has been updated since it was last checked or if it is unchanged. You can compare your HashMap/DashMap with it's previous version to see if anything has been changed or added.

Use cases

Simple use case when you need to return bool from a comparison:

use std::collections::HashMap;
use comparer::HashMapComparer;

let mut my_hashmap = HashMap::<u8, &str>::new();
let comparer = HashMapComparer::<u8, &str>::new();

my_hashmap.insert(1, "foo");
// HashMap has new values
assert_eq!(false, comparer.is_same_update(&my_hashmap));
// Hashmap has not received new values
assert_eq!(true, comparer.is_same_update(&my_hashmap));

my_hashmap.insert(2, "bar");
// HashMap has new values
assert_eq!(false, comparer.is_same_update(&my_hashmap));

Use case when you need to return values that have changed as a result of a comparison:

//Example usage
use std::collections::HashMap;
use comparer::HashMapComparer;

let comparer = HashMapComparer::<u8, &str>::new();
let mut my_hashmap = HashMap::<u8, &str>::new();
let mut results: Vec<HashMap<u8, &str>> = vec![];

my_hashmap.insert(1, "foo");
my_hashmap.insert(2, "bar");
my_hashmap.insert(4, "foo");

for i in 0..5 {
    my_hashmap.insert(i, "foo");
    results.push(comparer.update_and_compare(&my_hashmap).unwrap());
 }

assert_eq!(
    vec![
         // In the first comparison comparer always returns the whole hashmap because all values in it is new
         HashMap::<u8, &str>::from_iter(vec![(0, "foo"), (4, "foo"), (2, "bar"), (1, "foo")]),
         // Returns empty hashmap because value 1: "foo" didn't change
         HashMap::<u8, &str>::new(),
         // Returns hashmap with 2: "foo" because it was changed from 2: "bar"
         HashMap::<u8, &str>::from_iter(vec![(2, "foo")]),
         // Returns hashmap with 3: "foo" because it's a new value
         HashMap::<u8, &str>::from_iter(vec![(3, "foo")]),
         // Returns empty hashmap because value 4: "foo" didn't change
         HashMap::<u8, &str>::new(),
       ],
     results
 );

This library does not use any third-party crates, only crates from the standard rust library :]