How to convert a string to a number in TypeScript?

In TypeScript, converting strings to numbers typically involves several common methods. This section introduces several common methods with examples:

1. Using the Number Constructor

This is one of the most straightforward methods and is suitable for most cases. If the string is not a valid number, it returns NaN.

typescript
let str = "123";
let num = Number(str);
console.log(num); // Output: 123

2. Using the Unary Plus Operator

This method is concise and commonly used, as it directly converts the string to a number.

typescript
let str = "456";
let num = +str;
console.log(num); // Output: 456

3. Using parseInt() or parseFloat()

These functions are very useful when parsing integers or floating-point numbers from a string. parseInt() is used for integers without decimals, while parseFloat() is used for numbers with decimals.

typescript
let strInt = "789px";
let strFloat = "3.14someText";
let numInt = parseInt(strInt);
let numFloat = parseFloat(strFloat);

console.log(numInt); // Output: 789
console.log(numFloat); // Output: 3.14

• When you are certain that the entire string represents a number and you need a numeric value, use Number() or the unary plus operator.
• If the string contains non-numeric characters but you only need the numeric part (e.g., 123px converted to 123), use parseInt() or parseFloat().

By using these methods, you can flexibly choose the appropriate string-to-number conversion method based on your specific requirements.