@feugene/mu/src/internal/getRawTag.ts

Helpful TS utilities without dependencies

import root from './root'

/** Built-in value references. */
const symToStringTag = root.Symbol ? root.Symbol.toStringTag : undefined

/** Used for built-in method references. */
const objectProto = Object.prototype

/** Used to check objects for own properties. */
const hasOwnProperty = objectProto.hasOwnProperty

/**
 * Used to resolve the
 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
 * of values.
 */
const nativeObjectToString = objectProto.toString

/**
 * A specialized version of `baseGetTag` which ignores `Symbol.toStringTag` values.
 *
 * @private
 * @param {*} value The value to query.
 * @returns {string} Returns the raw `toStringTag`.
 */
export default function getRawTag(value: any): string {
  const isOwn = hasOwnProperty.call(value, symToStringTag),
    tag = value[symToStringTag]

  let unmasked = false

  try {
    value[symToStringTag] = undefined
    unmasked = true
  } catch (error) {}

  const result = nativeObjectToString.call(value)
  if (unmasked) {
    if (isOwn) {
      value[symToStringTag] = tag
    } else {
      delete value[symToStringTag]
    }
  }
  return result
}