How to convert string to number in TypeScript ?

In typescript, there are numerous ways to convert a string to a number. We can use the ‘+’ unary operator , Number(), parseInt() or parseFloat() function to convert string to number. Let’s demonstrate using a few examples.

Example 1:  The following code demonstrates converting a string to a number by using the ‘+’ unary operator.

Javascript

let str: string = "431";
console.log(typeof str);
let num = +str;
console.log(typeof num);

Output:

string
number

Example 2: The following code demonstrates converting a string to a number by using the Number() method. Instead of using the ‘+’ operator, we can use the Number() function to convert string to number. The string must be given as an argument to the Number() function.

Javascript

let str: string = "431";
console.log(typeof str);
let num = Number(str);
console.log(typeof num);

Output:

string
number

Example 3: Numbers can be of type float or int. To convert a string in the form of float to a number we use the parseFloat() function and to convert strings that do not have decimal to a number, the parseInt() function is used. 

Javascript

let str1:string = "102.2";
console.log(typeof str1);
let num = parseFloat(str1);
console.log(`${num}` + " is of type :" + typeof num);
let str2:string = "61";
console.log(typeof str2);
let num2 = parseInt(str2);
console.log(`${num2}` + " is of type :" + typeof num2);

Output:

string
102.2 is of type :number
string
61 is of type :number