How do you convert a string to a number in JavaScript?
TL;DR
In JavaScript, you can convert a string to a number using several methods. The most common ones are Number(), parseInt(), parseFloat(), and the unary plus operator (+). For example, Number("123") converts the string "123" to the number 123, and parseInt("123.45") converts the string "123.45" to the integer 123.
How do you convert a string to a number in JavaScript?
Using the Number() function
The Number() function converts a string to a number. It can handle both integer and floating-point numbers.
let str = '123';
let num = Number(str);
console.log(num); // 123
let floatStr = '123.45';
let floatNum = Number(floatStr);
console.log(floatNum); // 123.45Using the parseInt() function
The parseInt() function parses a string and returns an integer. It can also take a second argument, the radix (base) of the numeral system to be used.
let str = '123';
let num = parseInt(str);
console.log(num); // 123
let floatStr = '120.45';
let floatNum = parseInt(floatStr);
console.log(floatNum); // 120
let binaryStr = '1010';
let binaryNum = parseInt(binaryStr, 2);
console.log(binaryNum); // 10Using the parseFloat() function
The parseFloat() function parses a string and returns a floating-point number.
let floatStr = '123.45';
let floatNum = parseFloat(floatStr);
console.log(floatNum); // 123.45Using the unary plus operator (+)
The unary plus operator can be used to convert a string to a number. It is a shorthand method and works for both integers and floating-point numbers.
let str = '123';
let num = +str;
console.log(num); // 123
let floatStr = '123.45';
let floatNum = +floatStr;
console.log(floatNum); // 123.45Handling non-numeric strings
If the string cannot be converted to a number, these methods will return NaN (Not-a-Number).
let invalidStr = 'abc';
console.log(Number(invalidStr)); // NaN
console.log(parseInt(invalidStr)); // NaN
console.log(parseFloat(invalidStr)); // NaN
console.log(+invalidStr); // NaN