There were several ways to iterate javascript object, we have choose the appropriate approach based on our platform and version of javascript.

How to iterate Javascript Object:

A simple Javascript Object iteration goes like below.

Plain old Javascript:

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB"
}

for (var key in data) {
    console.log(key + " -> " + data[key]);
}

Output:

file -> 1623061746-report.xlsx
date -> 7/6/2021
size -> 41 KB

The same we can do with the below solutions.

Object.keys():

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB"
}

for (var key of Object.keys(data)) {
    console.log(key + " => " + data[key])
}

Output:

file => 1623061746-report.xlsx
date => 7/6/2021
size => 41 KB

Object.keys() foreach:

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB"
}

Object.keys(data).forEach(function(key) {
    console.log(key, data[key]);
});

Output:

file 1623061746-report.xlsx
date 7/6/2021
size 41 KB

Object.entries():

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB"
}

for (let [key, value] of Object.entries(data)) {
  console.log( `${key} : ${value}` );
}

Output:

file : 1623061746-report.xlsx
date : 7/6/2021
size : 41 KB

Object.entries() foreach:

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB"
}

Object.entries(data).forEach(
    ([key, value]) => console.log(key, value)
);

Output:

file 1623061746-report.xlsx 
date 7/6/2021 
size 41 KB

Iterating Nested Javascript Objects:

There is no surprise or second thought, all the above examples should work without any issues for nested objects also.

var data = {
    file: "1623061746-report.xlsx",
    date: "7/6/2021",
    size: "41 KB",
    inner_data: {
        file: "1623062754-report.xlsx",
        date: "7/6/2021",
        size: "41 KB"
    },
    inner_data_list: [
        {
            file: "1623065997-report.xlsx",
            date: "7/6/2021",
            size: "41 KB"
        },
        {
            file: "1623145510-report.xlsx",
            date: "8/6/2021",
            size: "44 KB"
        }
    ]
}

Object.entries(data).forEach(
    ([key, value]) => console.log(key, value)
);

Output:

References:

• More on Javascript Arrays

Happy Learning 🙂