How can I dynamically create an array/arraynames in JavaScript

Question

What I am trying to do is to create an array, whenever the element I am looking for is found (bank in my case). The first occurrence of the element should be placed in the first array and the second one in the second array and so on. Finally after all the elements are placed in separate arrays I push them onto a main array.

Is it possible to create the arrays with different names dynamically like Bank_1 ,Bank_2 and so on ?? and is this the right approach ?

var bankcontainer = [];
var bank = [];
for (let i = 0; i < length ;i++)
{
 let bankname = data.periods[0].decisions[i].bank;
 bank[i] = [];
 bank[i].push(bankname);
 bankcontainer.push(bank);
}

Example:

// Input: 
[{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }]
// Result:
{ bank_1: ["team1"], bank_3: ["team3"], bank_3: ["team3"] }

• prisar: bank[i] = []; is wrong.
• Clive Charles: I know, I am trying to improve this. Any suggestions ?
• prisar: give example of and array u want
• kornieff: Please provide sample data and outcome you are expecting.
• kornieff: @CliveCharles, good luck, see how answers just pop after problem got defined with sample data. Brush up on ES6 -- for loops are so 20th century :P.

Answer 1

const data = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }]
console.log(
 Object.fromEntries(
 data.map(
 (v, i) => [`bank_${++i}`, v.bank]
 )
 )
)

Answer 2

Iterate the array with Array.map() and create an entry of [key, value] from each item, and then convert to an object with Object.fromEntries():

const data = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }]
const result = Object.fromEntries(
 data.map((o, i) => [`bank_${i + 1}`, o.bank])
)
console.log(result)

If Object.fromEntries() is not supported, you can use Array.reduce():

const data = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }]
const result = data.reduce((r, o, i) => {
 r[`bank_${i + 1}`] = o.bank;
 return r;
}, {})
console.log(result)

Answer 3

this will create bank names dynamically

var bankcontainer = [];
var bank = [];
for (let i = 0; i < length ;i++)
{
 let bankname = data.periods[0].decisions[i].bank;
 const bank["bank_" + i] = [];
 bank["bank_" + i].push(bankname);
 bank = bank["bank_" + i];
}
bankcontainer.push(bank);

• Clive Charles: wouldn't all the elements go into the same array ?
• RyanNerd: Please comment your code so the person you are trying to help can understand what the code does and how it solves their problem.
• RyanNerd: Please comment your code so the person you are trying to help can understand what the code does and how it solves their problem.

Answer 4

Yes it is possible:

const myBanks = {};
const banks = ['BofA', 'Goldman Sachs', 'Stackoverflow Credit Union', 'Chase', 'Captial One 360'];
for (let i = 0; i < banks.length; i++)
{
 myBanks['Bank_' + i] = [banks[i]];
}
console.log(myBanks);

• Clive Charles: Thanks for answering my question: Now how can i append/push something on index 2 for example in "bank_1" ?

Answer 5

const input = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }];
const result = {};
input.forEach(
 (item, i) => { 
 result[`bank_${i +1}`] = [item.bank]; 
 }
);
console.log(result);

Answer 6

The map() can be used here to manipulate the object as follows:

let data = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }];
newData = data.map((item, index) => {
return {['bank_' + index] : [item.bank]}
})
console.log(newData);

Answer 7

Run forEach on data and create a dynamic key using the index, see below:

 let data = [{ bank: "team1" }, { bank: "team2" }, { bank: "team3" }];
 let newData = {};
 data.forEach((item, index) => {
 newData['bank_' + (index+1)] = [item.bank];
 })
 console.log(newData);