Example Sync logger and censor for WatermelonDB Sync https://github.com/Nozbe/WatermelonDB/blob/master/docs/Advanced/Sync.md 🍉

watermelon-sync-logger.js

// @flow

import { map, is } from 'rambdax'
import type { DirtyRaw } from '@nozbe/watermelondb/RawRecord'
import type { SyncLog } from '@nozbe/watermelondb/sync'

// beginning, end, length
const censorValue = (value: string): string =>
  `${value.slice(0, 2)}***${value.slice(-2)}(${value.length})`
const shouldCensorKey = (key: string): boolean =>
  key !== 'id' && !key.endsWith('_id') && key !== '_status' && key !== '_changed'

const censorRaw: DirtyRaw => DirtyRaw = map((value, key) =>
  shouldCensorKey(key) && is(String, value) ? censorValue(value) : value,
)
const censorConflicts = map(map(censorRaw))
const censorLog = (log: SyncLog): SyncLog => ({
  ...log,
  ...(log.resolvedConflicts ? { resolvedConflicts: censorConflicts(log.resolvedConflicts) } : {}),
})
const censorLogs = map(censorLog)

export default class SyncLogger {
  _logs: SyncLog[] = []

  newLog(): SyncLog {
    const log: SyncLog = {}
    this._logs.push(log)
    return log
  }

  get logs(): SyncLog[] {
    // censor logs before viewing them
    return censorLogs(this._logs)
  }
}