· hands on

Function Overloading Explained

This article provides a code example of a Calculator class in TypeScript that can add numbers or strings. The add method converts the inputs to numbers, adds them together, and returns the result as a number or string depending on the input types.

Please write two sentences here. Yeah, two.

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export type NumberLike = number | string;
 
export class Calculator {
  static add(a: number, b: number): number;
  static add(a: string, b: string): string;
  static add(a: NumberLike, b: NumberLike): NumberLike {
    const toNumber = (x: NumberLike): number => (typeof x === 'string' ? parseInt(x, 10) : x);
 
    const result = toNumber(a) + toNumber(b);
 
    if (typeof a === 'string' && typeof b === 'string') {
      return `${result}`;
    }
 
    return result;
  }
}
 
const result = Calculator.add('1', '1');
console.log(typeof result); // "string"
console.log(result); // "2"
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