the code 2 ** 8 not work in IE 11.

in the pulgins "buffer", The code below is not work in IE 11.

Buffer.prototype.readBigUInt64LE = defineBigIntMethod(function readBigUInt64LE (offset) {
offset = offset >>> 0
validateNumber(offset, 'offset')
const first = this[offset]
const last = this[offset + 7]
if (first === undefined || last === undefined) {
boundsError(offset, this.length - 8)
}

const lo = first +
this[++offset] * 2 ** 8 +
this[++offset] * 2 ** 16 +
this[++offset] * 2 ** 24

const hi = this[++offset] +
this[++offset] * 2 ** 8 +
this[++offset] * 2 ** 16 +
last * 2 ** 24

return BigInt(lo) + (BigInt(hi) << BigInt(32))
})