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The MarketThree.calcGlobalFeeRate() static method calculates the global fee rate and total value locked (TVL) metrics by comparing two market snapshots taken at different times.

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Usage

import { MarketThree } from "@exponent-labs/exponent-sdk";

// Create market snapshot data from historical and current state
const marketSnapshotCurrent = {
  syExchangeRate: 1.02,
  currentSpotPrice: 1.08,
  financials: currentFinancials,
  feeGrowthIndexGlobalPt: 1000000n,
  feeGrowthIndexGlobalSy: 2000000n,
  currentPrefixSum: 5000000n,
  snapshotTimeUnix: Math.floor(Date.now() / 1000),
};

const marketSnapshotHistory = {
  syExchangeRate: 1.01,
  currentSpotPrice: 1.07,
  financials: historicalFinancials,
  feeGrowthIndexGlobalPt: 900000n,
  feeGrowthIndexGlobalSy: 1800000n,
  currentPrefixSum: 4800000n,
  snapshotTimeUnix: Math.floor(Date.now() / 1000) - 86400, // 24 hours ago
};

const feeMetrics = MarketThree.calcGlobalFeeRate(
  marketSnapshotCurrent,
  marketSnapshotHistory
);

console.log("Total fee rate:", feeMetrics.totalFeeRate);
console.log("Total fees (base token):", feeMetrics.totalFeesInBaseToken);
console.log("TVL (base token):", feeMetrics.tvlInBaseToken);

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Parameters

ParameterTypeRequiredDescription
marketSnapshotDataCurrentMarketSnapshotDataYesCurrent market snapshot data
marketSnapshotDataHistoryMarketSnapshotDataYesHistorical market snapshot data for comparison

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MarketSnapshotData Type

{
  syExchangeRate: number;              // Current SY exchange rate
  currentSpotPrice: number;            // Spot price in format of 1 + percentage / 100
  financials: MarketThreeFinancials;   // Market financial data
  feeGrowthIndexGlobalPt: bigint;      // Global PT fee growth index
  feeGrowthIndexGlobalSy: bigint;      // Global SY fee growth index
  currentPrefixSum: bigint;            // Current prefix sum
  snapshotTimeUnix: number;            // Snapshot timestamp in Unix seconds
}

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Returns

Returns an object with: 
{
  totalFeeRate: number;
  totalFeesInBaseToken: number;
  tvlInBaseToken: number;
}
PropertyTypeDescription
totalFeeRatenumberThe calculated fee rate (total fees / TVL)
totalFeesInBaseTokennumberTotal fees earned in base token terms (PT + SY combined)
tvlInBaseTokennumberTotal value locked in base token terms (PT + SY liquidity)

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Calculation Details

The method performs the following calculations:
  1. Calculate PT fees in base token: 
    feePt = (feeGrowthPtCurrent - feeGrowthPtHistory) / currentPrefixSum
feePtInBaseToken = feePt * ptPriceInBaseToken
  2. Calculate SY fees in base token: 
    feeSy = (feeGrowthSyCurrent - feeGrowthSyHistory) / currentPrefixSum
feeSyInBaseToken = feeSy * syExchangeRate
  3. Calculate TVL: 
    ptLiquidity = ptBalance * ptPriceInBaseToken
syLiquidity = syBalance * syExchangeRate
tvl = ptLiquidity + syLiquidity
  4. Calculate total fee rate: 
    totalFeeRate = totalFeesInBaseToken / tvlInBaseToken
The PT price is calculated using time decay based on the time remaining until market expiration.