Run results for: spreadArray

Run details:

User agent: Mozilla/5.0 (Windows Phone 10.0; Android 6.0.1; Microsoft; Lumia 950 Dual SIM) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Mobile Safari/537.36 Edge/14.14393

Browser: Chrome Mobile 51

Operating system: Windows Phone 10.0

Device Platform: Lumia 950

Date tested: 7 years ago

Test name	Executions per second
spreadArray by ertema	110043.3 Ops/sec
spreadArray by kbakba	126027.9 Ops/sec
spreadArray with comparsion and concat	34098.2 Ops/sec
spreadArray with concat only	33443.1 Ops/sec
spreadArray with comparsion only	102031.8 Ops/sec

Script Preparation code:

var testArray = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('');
var delim = {'a': 1};

function spreadArrayErtema(array, delim) {
    return array.reduce(function (result, item) {
        result.push(delim, item);
        
        return result;
    }, []).slice(0, -1);
}

function spreadArrayKbakba(arr, delim) {
    var result = []
    for (var i = arr.length - 1; i >= 0; i--) {
        result.unshift(arr[i], delim);
    };
    result.pop();
    return result;
}


function spreadArrayComparsionAndConcat(array, delim) {
    return array.reduce(function (result, item, i) {
        return i === 0 ? result.concat(item) : result.concat(delim, item);
    }, []);
}

function spreadArrayConcat(array, delim) {
    return array.reduce(function (result, item, i) {
        return result.concat(delim, item);
    }, []).slice(0, -1);
}

function spreadArrayComparsion(array, delim) {
    return array.reduce(function (result, item, i) {
         if (i === 0) {
           result.push(item);
         } else {
           result.push(delim, item);
         }
      
        return result;
    }, []);
}

Tests:

spreadArray by ertema
spreadArrayErtema(testArray, delim);
spreadArray by kbakba
spreadArrayKbakba(testArray, delim);
spreadArray with comparsion and concat
spreadArrayComparsionAndConcat(testArray, delim);
spreadArray with concat only
spreadArrayConcat(testArray, delim);
spreadArray with comparsion only
spreadArrayComparsion(testArray, delim);

Run results for: spreadArray

Function that works like a join, but returns array

spreadArray by ertema

spreadArray by kbakba

spreadArray with comparsion and concat

spreadArray with concat only

spreadArray with comparsion only