Redact Record

A library to (partially) redact values with typesafety and zero dependencies. Allows redaction in nested objects.

Install

Sample:

import { redact } from 'redact-record'

const originalLog = {
  name: "Alice",
  action: "add ToDo"
}

// Redact `name` of the object. `name` will
// be redacted by only printing the first and last character
// other attributes will stay the same
const auditLog = redact(originalLog, {
  name: (name) => {
    if(name.length > 3) {
      const firstChar = name.charAt(0)
      const lastChar = name.charAt(name.length - 1)
      const redacted = "·".repeat(name.length - 2)
      return `${firstChar}${redacted}${lastChar}`·
    }
    else {
      return "·".repeat(name.length)
    }
  }
})

console.log(auditLog)

Will now return

{
  "action": "add ToDo",
  "name": "A···e",
}

It tries to be as simple as possible. The redact function takes the original object or value and a sanitizer object.

The sanitizer works as following:

// Assume the objects you want to redact are of type Log
type Log = {
    action: string;
    name: string;
    tags: string[];
}

// The sanitizer object type can be created as follows
type S = Sanitizer<Log>
// S will resolve to the type
//
// S = {
//     action?: (originalValue: string) => string;
//     name?: (originalValue: string) => string;
//     tags?: (originalTag: string) => string;
// } | (originalObject: Log) => Log
//
// To redact the complet object, or only individual fields

Installation

Usage

In order to redact an object, you need a sanitizer. This is either a function retrieving the original value and returning a redacted version of it, or an object to only redact individual attributes of the original object.

Single value examples

Change a string to [REDACTED]

redact("Hello World", () => '[REDACTED]'
// Result: "[REDACTED]"

Only print the first letter of the string, redact the rest

redact("Hello World", (original) => `${original.substring(0, 1)}...`)
// Result: "H..."

Array example

If the input is an array, the sanitizer function is called for each item.

redact(["Alice", "Bob"], (original) => `${original.substring(0, 1)}...`)
// Result: ["A...", "B..."]

Object example

If you want to redact an object, you can provide a sanitizer which follows the same attributes. Let's take the following example:

const input = {
    user: {
        name: 'Alice',
        age: 22,
    }
    action: "add Todo"
}

if you want redact the complete user information, but keep the action, you can do this

sanitizeValue(input, { user: (originalUser) => "REDACTED" })

If you only want to sanitize the name of the user, you could do this:

sanitizeValue(input, { user: { name: (originalName) => "REDACTED" } })