What Is A Keyword Argument?

Table of contents

• Definition
• Example or Use Case
• Conclusion

Definition

In programming, a keyword argument is an argument passed to a function or method by explicitly specifying the parameter name along with its value. Unlike positional arguments [→], the order in which keyword arguments are passed doesn't matter, because each argument is associated with the parameter name, making the function call more readable and less prone to errors.

Keyword arguments allow you to set default values for some parameters and pass only the values that need to be changed. This feature is common in many programming languages like Python and JavaScript.

Example or Use Case

Let’s consider an example in JavaScript with a function that calculates the total price of a product with optional tax and discount parameters.

Without Keyword Arguments (using object destructuring to simulate keyword arguments in JavaScript):

✅ Wrap📋
01: function calculateTotalPrice({ price, tax = 0.1, discount = 0 }) {
02:     const totalPrice = price + price * tax - discount;
03:     return totalPrice;
04: }
05: 
06: // Usage
07: const total = calculateTotalPrice({ price: 100, tax: 0.15, discount: 5 });
08: console.log(`The total price is $${total}`);

In this example, we pass the arguments using the parameter names (price, tax, discount). The order of these arguments does not matter because each one is explicitly labeled. This makes the function call clearer, and we can omit any argument that has a default value.

For instance, we can skip the discount parameter if we don't want to apply any discount:

✅ Wrap📋
01: const total = calculateTotalPrice({ price: 100, tax: 0.15 });
02: console.log(`The total price is $${total}`);

By specifying the parameters by name, we avoid confusion and make the code more maintainable.

Conclusion

Keyword arguments provide flexibility and clarity when passing values to functions. Unlike positional arguments, the order of keyword arguments doesn’t matter, making it easier to read and understand function calls, especially when there are many parameters or optional values. This is particularly useful in cases where only a few parameters need to be set, and others can take their default values.

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