function mergeSortedArray(a, b){

var merged = [],

aElm = a[0],

bElm = b[0],

i = 1,

j = 1;

if(a.length ==0)

return b;

if(b.length ==0)

return a;

/*

if aElm or bElm exists we will insert to merged array

(will go inside while loop)

to insert: aElm exists and bElm doesn't exists

or both exists and aElm < bElm

this is the critical part of the example

*/

while(aElm || bElm){

if((aElm && !bElm) || aElm < bElm){

merged.push(aElm);

aElm = a[i++];

}

else {

merged.push(bElm);

bElm = b[j++];

}

}

return merged;

}

console.log(mergeSortedArray([2,5,6,9], [1,2,3,29]));