array-vs-obj

"use strict";

const toMs = ( beg, end ) => {
	const sec = end[0] - beg[0];
	const ms = Math.floor( (end[1] - beg[1]) / 1000 );

	return sec * 1000 + ms;
};

const SIZE = 1000000;

let arr = [];
let obj = {};
for ( var i = 0; i < SIZE; ++i ) {
	let val = Math.floor( Math.random() * 256 );

	arr.push( val );
	obj[ "haha" + i ] = val;
}

let prev = process.hrtime();
let sum = 0;

for ( var i = 0; i < SIZE; ++i ) {
	let noop = "haha" + i;
	sum += arr[ i ];
}

let t1 = toMs( prev, process.hrtime() );
console.log( "Time cost: ", t1, "ms", sum );

arr.sort();

prev = process.hrtime();
sum = 0;
for ( var i = 0; i < SIZE; ++i ) {
	sum += obj[ "haha" + i ];
}

let t2 = toMs( prev, process.hrtime() );

console.log( "Time cost: ", t2, "ms", sum );

console.log( "Ratio t2/t1: ", t2 / t1 );