changes.ts

function oldSizeOfByteProperty(prop: {key: Uint8Array, value: Uint8Array}) {
  return prop.value.length;
}

function newSizeOfByteProperty(prop: {key: Uint8Array, value: Uint8Array}) {
  return sizeOfEncodedBytes(prop.key) + sizeOfEncodedBytes(prop.value);
}

function newSizeOfProperty(prop: {key: string, value: string}) {
  return sizeOfEncodedStr(prop.key) + sizeOfEncodedStr(prop.value);
}

/*
 Helper functions
*/

function sizeOfInt(i: number) {
  if (i < 0 || i > 0xffffffff) throw new Error('out of range');
  if(i < 0b11_1111) {
    return 1;
  } else if (i < 0b11_1111_1111_1111) {
    return 2;
  } else if (i < 0b11_1111_1111_1111_1111_1111_1111_1111) {
    return 4;
  } else {
    return 5;
  }
}

const UTF8_ENCODER = new TextEncoder();
function sizeOfEncodedStr(v: string) {
  const encoded = UTF8_ENCODER.encode(v);
  return sizeOfInt(encoded.length) + encoded.length;
}

function sizeOfEncodedBytes(bytes: Uint8Array) {
  return sizeOfInt(bytes.length) + bytes.length;
}