code: function isPrimitive(value) {
    if (value === null) {
      return true
    }
    if (value === undefined) {
      return false
    }
    if (typeof value === 'function') {
      return false
    }
    if ([ 'boolean', 'number', 'string' ].indexOf(typeof value) !== -1) {
      return true
    }
    if (value instanceof Date || value instanceof ArrayBuffer) {
      return true
    }
    return false
  }
docs: Whether an object is primitive. We consider functions non-primitives, lump Dates and ArrayBuffers into primitives.