# src/fee-calculator.js

    // @flow

    /**
     * @typedef {Object} FeeCalculator
     * @property {number} lamportsPerSignature lamports Cost in lamports to validate a signature
     * @property {number} targetLamportsPerSignature
     * @property {number} targetSignaturesPerSlot
     */
    export type FeeCalculator = {
      lamportsPerSignature: number,
      targetSignaturesPerSlot: number,
      targetLamportsPerSignature: number,
    };