Add element in object in array loop

Question

I am new to JavaScript I am trying to combine two object from two arrays

First Array

const TESTARRAY = [{
 id: 3,
 parameter1: 'x',
 parameter2: 'y',
 parameter3: 'z'
}, {
 id: 1,
 parameter1: 'u',
 parameter2: 'v',
 parameter3: 'w'
}, {
 id: 5,
 parameter1: 'q',
 parameter2: 'w',
 parameter3: 'e'
}]

Second array

var json = [{
 name: 'aaa'
}, {
 name: 'ccc'
}, {
 name: 'bbb'
}];

Expected Output

[{
 additional: "aaa",
 id: 3,
 parameter1: "x",
 parameter2: "y",
 parameter3: "z"
}, {
 additional: "ccc",
 id: 1,
 parameter1: "u",
 parameter2: "v",
 parameter3: "w"
}, {
 additional: "bbb",
 id: 5,
 parameter1: "q",
 parameter2: "w",
 parameter3: "e"
}]

Code I tried below in JSFiddle I try to loop the var and add the element to TESTARRAY but I am getting same value "bbb" anyone can guide me for better approach?

const TESTARRAY = [{
 id: 3,
 parameter1: 'x',
 parameter2: 'y',
 parameter3: 'z'
}, {
 id: 1,
 parameter1: 'u',
 parameter2: 'v',
 parameter3: 'w'
}, {
 id: 5,
 parameter1: 'q',
 parameter2: 'w',
 parameter3: 'e'
}]
var json = [{
 name: 'aaa'
}, {
 name: 'ccc'
}, {
 name: 'bbb'
}];
for (var key in json) {
 if (json.hasOwnProperty(key)) {
 TESTARRAY.map(i => i.additional = json[key].name)
 }
}
console.log(TESTARRAY)

• VLAZ: You don't have JSON. You have plain objects and plain arrays. JSON is a text serialisation format similar to XML. It will always be represented as a string.
• Arjun J Gowda: Just loop and update same index of the array for (const [k, v] of json.entries()) {TESTARRAY[k]['additional'] = v.name;}

Answer 1

You could map a new array with merged properties of the second array at the same index.

const
 array1 = [{ name: 'aaa' }, { name: 'ccc' }, { name: 'bbb' }],
 array2 = [{ id: 3, parameter1: 'x', parameter2: 'y', parameter3: 'z' }, { id: 1, parameter1: 'u', parameter2: 'v', parameter3: 'w' }, { id: 5, parameter1: 'q', parameter2: 'w', parameter3: 'e' }],
 merged = array1.map(({ name: additional }, i) => ({ additional, ...array2[i] }));
console.log(merged);

.as-console-wrapper { max-height: 100% !important; top: 0; }

• Shayne David: It works also thank you really appreciate your help.

Answer 2

Assuming the two arrays you want to combine are the same size. You can simply do something like this.

for (let i = 0; i < TESTARRAY.length; ++i)
{
 TESTARRAY[i] = {...json[i], ...TESTARRAY[i]};
}

• Shayne David: Its working thank you very much for your time and help

Answer 3

map second argument is an index of the current item, you can use that to reference your json variable.

const TESTARRAY = [{
 id: 3,
 parameter1: "x",
 parameter2: "y",
 parameter3: "z"
 },
 {
 id: 1,
 parameter1: "u",
 parameter2: "v",
 parameter3: "w"
 },
 {
 id: 5,
 parameter1: "q",
 parameter2: "w",
 parameter3: "e"
 }
];
var json = [{
 name: "aaa"
 },
 {
 name: "ccc"
 },
 {
 name: "bbb"
 }
];
const newTestArray = TESTARRAY.map((curr, index) => ({
 additional: json[index].name,
 ...curr
}));
console.log(newTestArray);