Run results for: Temp obj or in check

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.75 Safari/537.36

Browser: Chrome 55

Operating system: Windows

Device Platform: Other

Date tested: 8 years ago

Test name	Executions per second
Empty object with short method	989850.9 Ops/sec
Empty object with long method	1219276.6 Ops/sec
Full object with short method	1080830.2 Ops/sec
Full object with long method	998664.9 Ops/sec
Empty object with shorter method	1209607.9 Ops/sec
Full object with shorter method	1084573.1 Ops/sec

Script Preparation code:

var haystack = {};
var SIZE = 10000;
for (var i = 0; i < SIZE; i++) { haystack['a' + i] = i; }
var objA = {};
var objB = { haystack: haystack };
function get1(obj, key) { return (obj.haystack || {})[key] || -1; }
function get2(obj, key) { return (obj.haystack && key in obj.haystack) ? obj.haystack[key] : -1; }
function get3(obj, key) { return obj.haystack && obj.haystack[key] || -1; }
function randomKey() { return 'a' + Math.floor(Math.random() * SIZE); }

Tests:

Empty object with short method
get1(objA, randomKey());
Empty object with long method
get2(objA, randomKey());
Full object with short method
get1(objB, randomKey());
Full object with long method
get2(objB, randomKey());
Empty object with shorter method
get3(objA, randomKey());
Full object with shorter method
get3(objB, randomKey());

Run results for: Temp obj or in check

Is it faster to test if an object contains a sub-object before looking up keys on it, or substituting an empty object in a falsy check

Empty object with short method

Empty object with long method

Full object with short method

Full object with long method

Empty object with shorter method

Full object with shorter method