iterative-compare is a simple utility to help compare two ordered lists of data. It traverses each list by repeatedly advancing two iterators. It returns a promise which is fulfilled with the results when the comparison is complete. A comparison function can be passed to the constructor, which determines order and tests for missing items. An extraction function can be supplied to customize how the results are returned.
Install it:
$ npm install iterative-compare --savevar IterativeCompare = require('iterative-compare');
var leftList = [ "Adam", "John", "Phil", "Steve" ],
rightList = [ "Aaron", "John", "Phil", "Steven", "Travis" ];
function makeIter( list ) {
var i = 0;
return function() { return list[i++]; }
}
var comparer = new IterativeCompare();
comparer.compare(
makeIter( leftList ),
makeIter( rightList )
)
.then( function( results ) {
results.forEach( function(v) {
if( v.exists !== 'both' ) {
console.log( v.value + " only exists in the " + v.exists + " list" );
}
}
} );
/*
Outputs:
Aaron only exists in the right list
Adam only exists in the left list
Steve only exists in the left list
Steven only exists in the right list
Travis only exists in the right list
*/