Uint.toNumber

Convert Uint256 to JavaScript number

Try it Live

Run Uint examples in the interactive playground

Safe Integer Range

JavaScript numbers are 64-bit floats. Only integers in range [-2^53 + 1, 2^53 - 1] are safe.

Values exceeding Number.MAX_SAFE_INTEGER (9007199254740991) will throw.

// Safe values
Uint.toNumber(Uint(0n))                         // 0
Uint.toNumber(Uint(9007199254740991n))         // OK: MAX_SAFE_INTEGER

// Unsafe values throw
Uint.toNumber(Uint(9007199254740992n))         // Error: too large
Uint.toNumber(Uint(10n ** 18n))                // Error: too large

Usage Patterns

Array Indices

const index = Uint(5n)
const arr = [1, 2, 3, 4, 5, 6]
const value = arr[Uint.toNumber(index)]  // 6

Safe Conversion

function toNumberSafe(uint: BrandedUint256): number | null {
  try {
    return Uint.toNumber(uint)
  } catch {
    return null
  }
}

See Also

• fromNumber - Create from number
• toBigInt - Convert to BigInt (no limits)