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Overview

WithdrawalIndex represents the global withdrawal counter in the beacon chain. This counter increments monotonically for each withdrawal processed, providing a unique identifier for every withdrawal since the Shanghai/Capella upgrade. Type: bigint & { readonly [brand]: "WithdrawalIndex" }

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Key Concepts

  • Monotonic: Always increases, never resets
  • Global: Single counter for all withdrawals across all validators
  • EIP-4895: Introduced in Shanghai/Capella upgrade
  • Unique: Each withdrawal has a unique index

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Methods

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WithdrawalIndex.from(value)

Create WithdrawalIndex from number, bigint, or string. 
import { WithdrawalIndex } from '@tevm/primitives';

const idx1 = WithdrawalIndex.from(1000000n);
const idx2 = WithdrawalIndex.from(1000000);
const idx3 = WithdrawalIndex.from("0xf4240");

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WithdrawalIndex.toNumber(index)

Convert WithdrawalIndex to number. Throws if exceeds MAX_SAFE_INTEGER. 
const idx = WithdrawalIndex.from(1000000n);
const num = WithdrawalIndex.toNumber(idx); // 1000000

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WithdrawalIndex.toBigInt(index)

Convert WithdrawalIndex to bigint. 
const idx = WithdrawalIndex.from(1000000);
const big = WithdrawalIndex.toBigInt(idx); // 1000000n

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WithdrawalIndex.equals(a, b)

Check if two withdrawal indices are equal. 
const a = WithdrawalIndex.from(1000000n);
const b = WithdrawalIndex.from(1000000n);
WithdrawalIndex.equals(a, b); // true

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Usage Examples

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Track withdrawal history

import { WithdrawalIndex, ValidatorIndex } from '@tevm/primitives';

interface WithdrawalRecord {
  index: WithdrawalIndex;
  validatorIndex: ValidatorIndex;
  timestamp: number;
  amount: bigint;
}

const withdrawal: WithdrawalRecord = {
  index: WithdrawalIndex.from(1000000n),
  validatorIndex: ValidatorIndex.from(123456),
  timestamp: Date.now(),
  amount: 32000000000n, // 32 ETH in Gwei
};

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Query withdrawal range

import { WithdrawalIndex } from '@tevm/primitives';

const startIndex = WithdrawalIndex.from(1000000n);
const endIndex = WithdrawalIndex.from(1001000n);

// Query withdrawals in range [startIndex, endIndex]
const count = Number(endIndex - startIndex); // 1000 withdrawals

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References