gzip_blocks.js

// @ts-check
import { generate } from '@mapeo/mock-data'
import { encode } from '@mapeo/schema'
import { gzipSync } from 'node:zlib'

/**
 * @param {ReadonlyArray<any>} records
 * @param {(record: any) => number} getSize
 * @returns {number}
 */
const size = (records, getSize) =>
  records.reduce((result, record) => result + getSize(record), 0)

/**
 * @param {any} record
 * @returns {number}
 */
const getEncodedSize = (record) => encode(record).byteLength

/**
 * @param {any} record
 * @returns {number}
 */
const getEncodedGzippedSize = (record) =>
  gzipSync(encode(record), { level: 9 }).byteLength

const records = [
  ...generate('projectSettings', { count: 100 }),
  ...generate('observation', { count: 10_000 }),
  ...generate('field', { count: 1000 }),
  ...generate('preset', { count: 1000 }),
  ...generate('role', { count: 100 }),
  ...generate('deviceInfo', { count: 100 }),
  // `translation` and `track` are missing from `@mapeo/mock-data`
  // `icon` and `coreOwnership` had issues I did not investigate
]

console.log('Record count:', records.length)

const encodedSize = size(records, getEncodedSize)
console.log('Encoded size:', encodedSize, encodedSize / records.length, 'mean')

const encodedGzippedSize = size(records, getEncodedGzippedSize)
console.log(
  'Encoded + gzipped size:',
  encodedGzippedSize,
  encodedGzippedSize / records.length,
  'mean'
)

if (encodedSize < encodedGzippedSize) {
  console.log(
    `gzip made the result bigger by ${encodedGzippedSize - encodedSize} bytes`
  )
} else {
  console.log(
    `gzip made the result smaller by ${encodedSize - encodedGzippedSize} bytes`
  )
}