@wagmi/core/src/utils/deepEqual.ts

VanillaJS library for Ethereum

/** Forked from https://github.com/epoberezkin/fast-deep-equal */

export function deepEqual(a: any, b: any) {
  if (a === b) return true

  if (a && b && typeof a === 'object' && typeof b === 'object') {
    if (a.constructor !== b.constructor) return false

    let length: number
    let i: number

    if (Array.isArray(a) && Array.isArray(b)) {
      length = a.length
      if (length !== b.length) return false
      for (i = length; i-- !== 0; ) if (!deepEqual(a[i], b[i])) return false
      return true
    }

    if (
      typeof a.valueOf === 'function' &&
      a.valueOf !== Object.prototype.valueOf
    )
      return a.valueOf() === b.valueOf()
    if (
      typeof a.toString === 'function' &&
      a.toString !== Object.prototype.toString
    )
      return a.toString() === b.toString()

    const keys = Object.keys(a)
    length = keys.length
    if (length !== Object.keys(b).length) return false

    for (i = length; i-- !== 0; ) if (!Object.hasOwn(b, keys[i]!)) return false

    for (i = length; i-- !== 0; ) {
      const key = keys[i]

      if (key && !deepEqual(a[key], b[key])) return false
    }

    return true
  }

  // true if both NaN, false otherwise
  // biome-ignore lint/suspicious/noSelfCompare: using
  return a !== a && b !== b
}