Get the hash of an object

hash-object.ts

import decircular from 'decircular'
import isObject from 'is-obj'
import sortKeys from 'sort-keys'
import { type LiteralUnion } from 'type-fest'

export type Encoding = 'hex' | 'base64' | 'buffer'
export type Algorithm = LiteralUnion<'sha1' | 'sha256' | 'sha512', string>

export type Options = {
  /**
   * The encoding of the returned hash.
   *
   * @default 'hex'
   */
  readonly encoding?: Encoding

  /**
   * _Don't use `'md5'` or `'sha1'` for anything sensitive. [They're insecure.](http://googleonlinesecurity.blogspot.no/2014/09/gradually-sunsetting-sha-1.html)_
   *
   * @default 'sha512'
   */
  readonly algorithm?: Algorithm
}

export type BufferOptions = {
  readonly encoding: 'buffer'
} & Options

function normalizeObject<T>(object: T): T {
  if (typeof object === 'string') {
    return object.normalize('NFD') as T
  }

  if (Array.isArray(object)) {
    return object.map((element: any) => normalizeObject(element)) as T
  }

  if (isObject(object)) {
    return Object.fromEntries(
      Object.entries(object).map(([key, value]) => [
        key.normalize('NFD'),
        normalizeObject(value)
      ])
    ) as T
  }

  return object
}

export default async function hashObject(
  object: Record<string, any>,
  { encoding = 'hex', algorithm = 'sha512' }: BufferOptions | Options = {}
): Promise<string | Uint8Array> {
  if (!isObject(object)) {
    throw new TypeError('Expected an object')
  }

  const normalizedObject = normalizeObject(decircular(object))
  const stableJsonInput = JSON.stringify(
    sortKeys(normalizedObject, { deep: true })
  )

  const encoder = new TextEncoder()
  const data = encoder.encode(stableJsonInput)
  const algorithmWebCrypto =
    algorithm === 'sha1'
      ? 'SHA-1'
      : algorithm === 'sha256'
        ? 'SHA-256'
        : 'SHA-512'
  const hashBuffer = await crypto.subtle.digest(algorithmWebCrypto, data)

  if (encoding === 'buffer') {
    return new Uint8Array(hashBuffer)
  }

  const hashArray = Array.from(new Uint8Array(hashBuffer))

  if (encoding === 'hex') {
    return hashArray.map((b) => b.toString(16).padStart(2, '0')).join('')
  } else if (encoding === 'base64') {
    // eslint-disable-next-line unicorn/prefer-code-point
    return btoa(String.fromCharCode(...hashArray))
  } else {
    throw new Error(`Unsupported encoding: ${encoding}`)
  }
}

Slight modification to https://github.com/sindresorhus/hash-object to support non-node.js environments using the web crypto API.