What is the best way to convert a string to a number in TypeScript?

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1

What is the best way to convert a string to a number in TypeScript?

Given a string representation of a number, how can I convert it to a number type in TypeScript?

For example:

var numberString: string = "1234";
var numberValue: number = /* what should I do with `numberString`? */;

What are the recommended methods for string to number TypeScript conversion, and how do they differ in behavior?

2

You can use parseInt() is a common method for converting a string to an integer. It parses the string from the beginning and returns the first integer value it encounters.

If it can’t convert the string, it returns NaN. You can specify the base (radix) for the conversion, though it’s typically used with base 10 for decimal numbers.

let numberString: string = "1234";
let numberValue: number = parseInt(numberString, 10);

console.log(numberValue);  // 1234

Note: If numberString contains non-numeric characters (like “123abc”), parseInt will return the integer part (123 in this case). If the string cannot be converted, it returns NaN.

Hope this helps :slight_smile:

3

You can also use parseFloat() as it works similarly to parseInt(), as @dimplesaini.230 said, but parseFloat() is used to parse floating-point numbers from a string. It is a better choice when dealing with decimal numbers, as it handles fractional values.

let numberString: string = "1234.56";
let numberValue: number = parseFloat(numberString);

console.log(numberValue);  // 1234.56

Like parseInt(), if numberString contains non-numeric characters, parseFloat() will return the number parsed up to the point where it encounters an invalid character. If the string can’t be parsed as a number, it will return NaN.

Hope this helps you :slight_smile:

4

How about you use a unary plus (+) operator

The unary plus (+) is the most concise and efficient way to convert a string to a number in TypeScript. It attempts to convert the string to a number directly and returns NaN if the conversion fails. This is a quick and effective method, especially for simple cases.

let numberString: string = "1234";
let numberValue: number = +numberString;

console.log(numberValue);  // 1234

This method directly converts the string to a number, and if the string contains any non-numeric characters, it returns NaN.