TypeScript type conversion example
TypeScript Basic: Exercise-6 with Solution
Write a TypeScript program that converts a variable of one type to another using type assertions and type conversion functions like parseInt().
Sample Solution:
TypeScript Code:
// Using type assertion to convert a string to a number
let str_num: string = "100";
let numberFromAssertion: number = parseInt(str_num); // Using parseInt to convert
console.log("Number from assertion:", numberFromAssertion);
// Using type assertion to convert a number to a string
let numberValue: number = 200;
let stringFromAssertion: string = numberValue.toString(); // Using toString() method to convert
console.log("String from assertion:", stringFromAssertion);
Explanations:
In the exercise above -
- First, declare a ‘str_num’ variable containing the string "100" and a 'numberValue' variable containing the number 200.
- To convert a string to a number, we use "parseInt()" to parse the string and obtain a numeric value. We assign the result to the 'numberFromAssertion' variable. This is a type assertion because we are telling TypeScript that we expect the result to be a number.
- To convert a number to a string, we use the toString() method available for numbers. We assign the result to the 'stringFromAssertion' variable, again as a type assertion.
- Finally we log the converted values to the console to verify the type conversion.
Output:
"Type of temp:", "undefined" "My Variable:", "Hello, TypeScript!"
TypeScript Editor:
See the Pen TypeScript by w3resource (@w3resource) on CodePen.
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