for...in and for...of

You can use the for...in and for...of statements to work with loops.

The for...in loop iterates over all enumerable properties of an object.

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for (variable in object) {
  // code to be executed
}

For example, you can iterate over the properties within an object as follows:

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const student = {
  name: 'CodeFriends',
  age: 20,
};

for (let key in student) {
  console.log(key, ':', student[key]);
}

The code above will output the following:

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name: CodeFriends
age: 20

The for...of loop is used to iterate over values of iterable objects (e.g., Arrays, Strings, Sets, Maps, etc.).

Using for...of, you can retrieve each item in an array one by one.

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for (variable of iterable) {
  // code block
}

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const fruits = ['Apple', 'Banana', 'Grapes'];

for (let fruit of fruits) {
  console.log(fruit);
}

This code will output:

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Apple
Banana
Grapes

You can also use for...of with strings, as shown below:

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const serviceName = 'CodeFriends';

for (let char of serviceName) {
  console.log(char);
}

This code will output:

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C
o
d
e
F
r
i
e
n
d
s

In summary, for...in iterates over object properties, whereas for...of iterates over values of iterable objects.