Javascript两个数组合并（键和值）

Question

I have two array. I want to merge this two arrays into one array. One array consisting keys and another one values.My array looks like

productId = [8,7,9];//Key Element
quantity = ["5","1","3"];//Value Element
//expected new array
newarray = {
    "8": 5,
    "7": 1,
    "9": 3
}

I already tried to merge these arrays, in this way

var newArray = {};
for(var i=0; i< productId.length; i++){
  newArray[productId[i]] = quantity [i];
}
console.log(newArray);

It returns

Object [ <7 empty slots>, "5", "1", "3" ]

Answer 1

Try the following:

 var productId = [8,7,9];//Key Element var quantity = ["5","1","3"];//Value Element var obj = {}; var i = 0; for(var k of productId) { obj[k] = parseInt(quantity[i]); i++; } console.log(obj); 

Answer 2

You are working in firefox so you may get this type of issue because the problem might be caused at how Firefox' console.log has interpreted the input object.

Please look here

Empty slots in JavaScript objects?

Try this

 var productId = [8,7,9]; var quantity = ["5","1","3"]; var newarray = {}; productId.forEach((key, i) => newarray[key] = quantity[i]); console.log(newarray); 

Answer 3

Your new "array" is not an Array but an Object .

You can iterate on one of the arrays using Array.reduce to construct the object.

Something like that:

 const arr1 = ['8', '2', '4']; const arr2 = ['28', '12', '45']; const result = arr1.reduce((obj, currentItem, index) => { obj[currentItem] = arr2[index]; return obj; }, {}); console.log(result);