Performance: isFunction

[lcnvdl]

I'm testing the performance of iio.isFunction in different browsers.

http://jsperf.com/isfunction-performance/2

Tests:

isFunction1 = function(fn) {
    return toString.call(fn) === "[object Function]";
}

isFunction2 = function(fn) {
    return typeof(fn) === "function";
}
isFunction3 = function(fn) {
    return (fn instanceof Function);
}

// iio.isFunction
isFunction4 = function(fn) {
    var getType = {};
    return fn && getType.toString.call(fn) === '[object Function]';
}

Results:

Chrome 35.0.1916

• isFunction1: 6,400,000 ops/sec (worst)
• isFunction2: 441,000,000 ops/sec (better)
• isFunction3: 17,800,000 ops/sec
• isFunction4: 6,600,000 ops/sec

Firefox 31.0

• isFunction1: 62,400,000 ops/sec
• isFunction2: 868,200,000 ops/sec (better)
• isFunction3: 584,300,000 ops/sec
• isFunction4: 38,100,000 ops/sec (worst)

IE 10.0

• isFunction1: 8,900,000 ops/sec
• isFunction2: 138,900,000 ops/sec (better)
• isFunction3: 121,300,000 ops/sec
• isFunction4: 7,400,000 ops/sec (worst)

My recomendation

iio.isFunction = function (fn) {
    return typeof fn === 'function';
}

[sbiermanlytle]

Interesting, I wonder where I found that one.. Thanks for the recommendation, the optimal function has been integrated in 1.3 and added to 1.2