Typescript Examples: Type Casting and Type Conversions

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Table of Contents

Cast string to number

Same as Javascript, use parseInt()

const num = parseInt("45");

console.log(typeof num);
// 'number'

Cast number to string

Just use toString(), but must assign to a variable first.

const num = 45
const numStr = num.toString();

console.log(typeof numStr);
// 'string'

Convert object to array of key-value objects

const peopleObj = {
  john: {
    name: "john",
    age: 20
  },
  mary: {
    name: "mary",
    age: 22
  }
}

const peopleArray = Object.keys(peopleObj).map(key => peopleObj[key]);

console.log(peopleArray);
// [ { name: 'john', age: 20 }, { name: 'mary', age: 22 } ]

Dialogue & Discussion