JS to sort an array of structures by one or more properties

multiSortArrayStruct.js

function propComparator(sortBy){
	
	return function(a,b){
	
        let fieldsToSortBy = sortBy.split(",");

        for ( x = 0; x < fieldsToSortBy.length; x++ ) {
		
		let results = 0;
		
		// check if we're comparing dates, handle accordingly 
		// TBD
		
		// check if we're comparing numerics, handle accordingly
            	if ( !isNaN( a[fieldsToSortBy[x]] ) && !isNaN( b[fieldsToSortBy[x]] ) ){
                	results = a[fieldsToSortBy[x]] - b[fieldsToSortBy[x]];
            	} else {			
			// otherwise we're comparing strings
			results = a[fieldsToSortBy[x]].localeCompare( b[fieldsToSortBy[x]] );
		}
			
		if ( results != 0 )
			return results;
        }

		// if we go thru all sort criteria w\o a "winner", then we call a tie
        	return 0;
     	}
}

// EXAMPLE USAGE: presidents.sort( propComparator('lastName,firstName') );

Given this array of structures:

test2 = [ { firstName: "Gerald", lastName: "Ford" }, { firstName: "James", lastName: "Carter" }, { firstName: "Ronald", lastName: "Reagan" }, { firstName: "George", lastName: "Bush" }, { firstName: "William", lastName: "Clinton" }, { firstName: "George", lastName: "Bush" }, { firstName: "Barack", lastName: "Obama" }, { firstName: "Donald", lastName: "Trump" }, { firstName: "Joseph", lastName: "Biden" } ]

You can define the propComparator function, and then leverage it in the following ways:

presidents.sort( propComparator('lastName,firstName'); // sorts array by lastName, then by firstName
presidents.sort( propComparator('firstName,lastName'); // sorts array by firstName, then by lastName

You get the idea. Just remember, the larger the array of structures, and the more criteria by which you sort, the longer the sorting task may take to complete.