Combine array of objects on every third elemnt of the first array

I have two different sets of array of objects.

        arr1 = [
                   {name: 'abcd', class: 'ef', pattern:'ds'}, 
                   {name: 'wdw', class: 'ef', pattern:'123'},
                   {name: 'wdd', class: 'ef', pattern:'d12sasds'},
                   {name: 'wdwd', class: 'a', pattern:'sd'},
                   {name: 'abcd', class: 'ef', pattern:'ds'}, 
                   {name: 'wdw', class: 'ef', pattern:'123'},
                   {name: 'wdd', class: 'ef', pattern:'d12sasds'},
                   {name: 'wdwd', class: 'a', pattern:'sd'},
                ]

and

arr2 = [
                   {height: '123', weight:'12'}, 
                   {height: '123', weight:'12'}, 
       ]

I want to combine these two array and put every element from the arr2 into arr1 on the third position..

so my new array looks like

newarr = [
                   {name: 'abcd', class: 'ef', pattern:'ds'}, 
                   {name: 'wdw', class: 'ef', pattern:'123'},
                   {name: 'wdd', class: 'ef', pattern:'d12sasds'},
                   {height: '123', weight:'12'}, 
                   {name: 'wdwd', class: 'a', pattern:'sd'},
                   {name: 'abcd', class: 'ef', pattern:'ds'}, 
                   {name: 'wdw', class: 'ef', pattern:'123'},
                   {height: '123', weight:'12'},
                   {name: 'wdd', class: 'ef', pattern:'d12sasds'},
                   {name: 'wdwd', class: 'a', pattern:'sd'},
       ]

Answer

function a(arr1,arr2){
    let arr3 = [];
    let i,n
    i = 0;
    n = 0;
    while (i < arr1.length) {
        if(i != 0 && String(i/3).split(".").length == 1 && n < arr2.length){
            arr3[arr3.length] = arr2[n];
            n++;
        }
        arr3[arr3.length] = arr1[i];
        i++;
    }
    return arr3;
}
arr1 = [
    {name: 'abcd', class: 'ef', pattern:'ds'}, 
    {name: 'wdw', class: 'ef', pattern:'123'},
    {name: 'wdd', class: 'ef', pattern:'d12sasds'},
    {name: 'wdwd', class: 'a', pattern:'sd'},
    {name: 'abcd', class: 'ef', pattern:'ds'}, 
    {name: 'wdw', class: 'ef', pattern:'123'},
    {name: 'wdd', class: 'ef', pattern:'d12sasds'},
    {name: 'wdwd', class: 'a', pattern:'sd'}
];
arr2 = [
    {height: '123', weight:'12'}, 
    {height: '123', weight:'12'}
];
console.log(a(arr1,arr2));