Javascript: Looping through Keys/Values of an Object

The examples below show you how to loop through keys/values of a given object in Javascript.

Example 1: Using Object.entries()

The entries() method returns an array of a given object. It’s supported in all modern browsers and Node.js 7+.

// Kindacode.com
const obj = {
  key1: "value 1",
  key2: "value 2",
  key3: "value 3",
  key4: "value 4",
};

// Using forEach
console.log('Using forEach:');
Object.entries(obj).forEach(([key, value]) => {
  console.log(`Key: ${key}, Value: ${value}`);
});

// Using map()
console.log('Using map():');
Object.entries(obj).map(([key, value]) => {
  console.log(`Key: ${key}, Value: ${value}`);
});

// Using for ... of
console.log('Using for ... of:');
for (const [key, value] of Object.entries(obj)) {
  console.log(`Key: ${key}, Value: ${value}`);
}

Output:

Using forEach:
Key: key1, Value: value 1
Key: key2, Value: value 2
Key: key3, Value: value 3
Key: key4, Value: value 4

Using map():
Key: key1, Value: value 1
Key: key2, Value: value 2
Key: key3, Value: value 3
Key: key4, Value: value 4

Using for ... of:
Key: key1, Value: value 1
Key: key2, Value: value 2
Key: key3, Value: value 3
Key: key4, Value: value 4

Example 2: Using Object.keys()

The code:

// Kindacode.com
const obj = {
  'color1': 'Blue',
  'color2': 'Red',
  'color3': 'Orange'
};

for (let key of Object.keys(obj)) {
  console.log(`Key: ${key}, Value: ${obj[key]}`);
}

Output:

Key: color1, Value: Blue
Key: color2, Value: Red
Key: color3, Value: Orange

Final Words

We’ve explored some common techniques that can be used to iterate through keys/values of an object. If you’d like to learn more about vanilla Javascript and TypeScript, take a look at the following articles:

• Javascript: Set HTML lang attribute programmatically
• Javascript: 5 ways to create a new array from an old array
• Javascript: Display float with 2 decimal places (3 examples)
• TypeScript Example: Default Function Parameters
• TypeScript: Intersection Type Examples

You can also check out our TypeScript category page for the latest tutorials and examples.