7th grader homework checker - TypeScript functions that can be used to calculate the area and perimeter of a circle

math-homework-check.ts

const PI = 3.14;

const CircleSize = {
  Quarter: 0.25,
  Half: 0.5,
  Full: 1,
};

type WithRadiusOrDiameter = { r?: number; d?: number };
type WithPercent = { percent: typeof CircleSize[keyof typeof CircleSize] };

type AreaOptions = WithRadiusOrDiameter & WithPercent;
type PerimeterOptions = WithRadiusOrDiameter & WithPercent;
type SolveOptions = WithRadiusOrDiameter &
  WithPercent & {
    area?: number;
    perimeter?: number;
  };

function areaOfCircle(options: AreaOptions) {
  let radius = options.r ?? options.d! / 2;
  let percent = options.percent ?? CircleSize.Full;

  if (!radius) {
    throw new Error("Radius or diameter is required");
  }

  return PI * radius ** 2 * percent;
}

function perimeterOfCircle(options: PerimeterOptions) {
  let radius = options.r ?? options.d! / 2;
  let percent = options.percent ?? CircleSize.Full;

  if (!radius) {
    throw new Error("Radius or diameter is required");
  }

  const fullPerimeter = 2 * PI * radius;

  if (percent === CircleSize.Full) {
    return fullPerimeter;
  }

  return fullPerimeter * percent + 2 * radius;
}

function printAnswer(options: Required<SolveOptions>): void {
  for (const k of Object.keys(options)) {
    const key = k as keyof typeof options;

    if (typeof options[key] === "number") {
      options[key] = Number(options[key].toFixed(2));
    }
  }

  console.table(options);
}

function solve(options: SolveOptions): any {
  if (options.r) {
    return printAnswer({
      area: areaOfCircle(options),
      d: options.r * 2,
      r: options.r,
      perimeter: perimeterOfCircle(options),
      percent: options.percent ?? CircleSize.Full,
    });
  }

  if (options.d) {
    return printAnswer({
      area: areaOfCircle(options),
      d: options.d,
      r: options.d / 2,
      perimeter: perimeterOfCircle(options),
      percent: options.percent ?? CircleSize.Full,
    });
  }

  if (options.area) {
    const r = Math.sqrt(options.area / (PI * options.percent));
    return solve({ ...options, r });
  }

  if (options.perimeter) {
    let r: number;

    if (options.percent === CircleSize.Full) {
      r = options.perimeter / (2 * PI);
    } else {
      r = options.perimeter / (2 * PI * options.percent + 2);
    }

    return solve({ ...options, r });
  }

  throw new Error("No options provided");
}

// solve({
//   percent: CircleSize.Quarter,
//   perimeter: 57.12
// });