JavaScript Loops - Looping Through Function Properties

JavaScript allows you to loop through the properties of an object using various loop constructs. When it comes to objects that have functions as properties, you can iterate through these functions for various purposes, such as executing them dynamically. In this guide, we'll explore how to loop through function properties in JavaScript objects with practical examples.

Creating an Object with Function Properties

Let's start by creating an object with function properties. In this example, we'll define an object called calculator with functions for basic arithmetic operations:

const calculator = {
    add: function(a, b) {
        return a + b;
    },
    subtract: function(a, b) {
        return a - b;
    },
    multiply: function(a, b) {
        return a * b;
    },
    divide: function(a, b) {
        return a / b;
    }
};
    

Looping Through Function Properties with for...in

You can loop through the function properties of an object using a for...in loop. This loop iterates through all enumerable properties, including functions:

for (const operation in calculator) {
    if (typeof calculator[operation] === 'function') {
        console.log('Operation:', operation);
        const result = calculator[operation](10, 5);
        console.log('Result:', result);
    }
}
    

This loop iterates through each property in the calculator object, checks if it's a function, and if it is, executes the function with sample values.

Output:

Operation: add
Result: 15
Operation: subtract
Result: 5
Operation: multiply
Result: 50
Operation: divide
Result: 2
    

Conclusion

Looping through function properties in JavaScript objects can be useful for dynamic execution of functions and for inspecting an object's methods. The for...in loop is a handy way to accomplish this task, especially when working with objects that have various function properties.

Experiment with different objects and functions to explore the power of iterating through function properties using JavaScript loops.