In JavaScript, + and parseInt() are two commonly used methods to convert values into numbers. While they both serve the purpose of the conversion they have different use cases, behaviors, and characteristics. This article explores the differences between the + operator and the parseInt() function providing the clear understanding of when to the use each.
What is +?
The + operator in JavaScript is primarily known as the addition operator. However, when used before a value it acts as a unary operator to the convert that value into the number.
The + operator when used as a unary operator attempts to the convert its operand to the number. If the operand is already a number, it returns the number itself. If the operand is not a number it converts it to the number using JavaScript's type conversion rules.
Syntax
+value
Example
let str = "123";
let num = +str;
console.log(num);
Output:
123
What is parseInt()?
The parseInt() function in JavaScript parses a string and returns an integer. It can handle different bases and stops parsing when it a non-numeric character.
The parseInt() takes a string and an optional radix as the arguments. It converts the string to an integer parsing until it a non-numeric character.
Syntax
parseInt(string, radix)
Example
let str = "123";
let num = parseInt(str, 10);
console.log(num);
Output:
123
Difference Between + and parseInt() in javascript:
| Characteristics | + | parseInt() |
|---|
| Usage | Converts value to the number | The Parses string and returns an integer |
| Syntax | +value | parseInt(string, radix) |
| Base Handling | Converts to base 10 | Can handle different bases (radix) |
| Stops at Non-numeric Char | No | Yes |
| Non-convertible Values | Returns NaN | Returns NaN |
| Example | + "123" // 123 | parseInt("123", 10) // 123 |
| Conversion Scope | Works on the various types | Works on the strings |
Conclusion
Both + and parseInt() are useful for the converting values to the numbers in JavaScript but they serve different purposes. The + operator is a quick and simple way to the convert various types to numbers while parseInt() is specifically designed to the parse strings into the integers with the support for the different numerical bases. Understanding the differences between these methods allows developers to the choose the appropriate tool based on their specific needs.