Add arrayEquals function

[aleclarson]

export function arrayEquals(a: unknown[], b: unknown[]): boolean {
  return (
    a === b ||
    (a.length === b.length && a.every((val, index) => Object.is(val, b[index])))
  )
}

Caveats

• Sparse arrays are not supported by the proposed implementation.

   const a = [1,  , 3]
   const b = [1, 2, 3]
   
   arrayEquals(a, b) // => true

[aleclarson]

Alternative implementation

A bit more flexible when working with optional arrays:

export function arrayEquals(
  a: unknown[] | null | undefined,
  b: unknown[] | null | undefined,
): boolean {
  if (!a) {
    return !b
  }
  if (!b) {
    return false
  }
  return (
    a === b ||
    (a.length === b.length && a.every((val, index) => Object.is(val, b[index])))
  )
}

Points of interest

1. Is it too weird to return true for arrayEquals(undefined, null)? I think it's more practical to treat them identically, since it's bad practice to do otherwise the majority of the time.