How To Convert String To Int In Javascript

In this blog post, we will dive into the process of converting a string to an integer in JavaScript. This might come in handy when you are working with user input, data from APIs, or any other source where numbers are represented as strings.

JavaScript parseInt() Function

The most common way to convert a string to an integer in JavaScript is to use the built-in parseInt() function. The parseInt() function takes a string as its first argument and returns an integer in the specified radix (base). The radix is optional, and if not provided, it defaults to base 10.

Here’s an example:

    const str = "42";
    const num = parseInt(str);
    console.log(num); // 42
    

You can also provide a radix as the second argument:

    const hexStr = "2A";
    const hexNum = parseInt(hexStr, 16);
    console.log(hexNum); // 42
    

JavaScript Number() Function

Another way to convert a string to an integer is to use the Number() function. This function attempts to convert the given string into a number. If it cannot be converted, it returns NaN (Not-a-Number). However, the Number() function returns a floating-point number, so you may need to use Math.floor(), Math.ceil(), or Math.round() to turn it into an integer.

Here’s an example:

    const str = "42";
    const num = Number(str);
    console.log(num); // 42
    

If you want to get an integer value, you can use Math.floor():

    const str = "42.7";
    const num = Math.floor(Number(str));
    console.log(num); // 42
    

Unary Plus (+) Operator

Another concise way to convert a string to an integer in JavaScript is to use the unary plus (+) operator. When applied to a string that can be converted to a number, it returns the numeric value. However, like the Number() function, it returns a floating-point number, so you may need to use Math.floor(), Math.ceil(), or Math.round() to turn it into an integer.

Here’s an example:

    const str = "42";
    const num = +str;
    console.log(num); // 42
    

Combining the unary plus operator with Math.floor():

    const str = "42.7";
    const num = Math.floor(+str);
    console.log(num); // 42
    

Conclusion

In this blog post, we explored three methods to convert a string to an integer in JavaScript: the parseInt() function, the Number() function, and the unary plus operator. Depending on your specific use case, you can choose the method that suits you best. Happy coding!