CODEWITHSUNDEEP
javascript
Ben
Ben

Reputation: 3357

Improve javascript number rounding

I was wondering if there's a way to improve and make this function faster, less resource consuming and more readable:

calculateMerchantEarnings(original_price) {
    const processor_percentage = Math.round((original_price * 0.029 + Number.EPSILON) * 100) / 100;
    const processor_flat = 30; // in cents
    const myfees_and_processing_fees = processor_percentage + processor_flat + 100;
    const final_price_minus_deductions = original_price - myfees_and_processing_fees;
    const final_price_in_cents = Math.round((final_price_minus_deductions + Number.EPSILON) * 100) / 100;
    return (
      Math.round((final_price_in_cents / 100 + Number.EPSILON) * 100) / 100
    );
  }

What I do is:

  1. Pass the original_price in cents
  2. Calculate CC Processor percentage fees
  3. Add my fees ($1) and the processor's percentage and flat fee
  4. calculate the final price by deducting the total fees from the original_price
  5. Round up the final price in cents
  6. Convert the final price to dollars and round up

I have a feeling I may be able to do all this with one line :)

Upvotes: 1

Views: 41

Answers (1)

Nina Scholz
Nina Scholz

Reputation: 386550

Basically, you could add all into a single expression.

function calculateMerchantEarnings(original_price) {
    const processor_percentage = Math.round((original_price * 0.029 + Number.EPSILON) * 100) / 100;
    const processor_flat = 30; // in cents
    const myfees_and_processing_fees = processor_percentage + processor_flat + 100;
    const final_price_minus_deductions = original_price - myfees_and_processing_fees;
    const final_price_in_cents = Math.round((final_price_minus_deductions + Number.EPSILON) * 100) / 100;
    return Math.round((final_price_in_cents / 100 + Number.EPSILON) * 100) / 100;
}

const fn = x => Math.round(x * 0.971 - 130) / 100;

console.log(calculateMerchantEarnings(1000));
console.log(fn(1000));

Upvotes: 2

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