typedarray.ts

import { inspectList, inspectProperty, truncate, truncator } from './helpers.js'
import type { Inspect, Options } from './types.js'

type TypedArray =
  | Int8Array
  | Uint8Array
  | Uint8ClampedArray
  | Int16Array
  | Uint16Array
  | Int32Array
  | Uint32Array
  | Float32Array
  | Float64Array

const getArrayName = (array: TypedArray) => {
  // We need to special case Node.js' Buffers, which report to be Uint8Array
  // @ts-ignore
  if (typeof Buffer === 'function' && array instanceof Buffer) {
    return 'Buffer'
  }
  if (array[Symbol.toStringTag]) {
    return array[Symbol.toStringTag]
  }
  return array.constructor.name
}

export default function inspectTypedArray(array: TypedArray, options: Options): string {
  const name = getArrayName(array)
  options.truncate -= name.length + 4
  // Object.keys will always output the Array indices first, so we can slice by
  // `array.length` to get non-index properties
  const nonIndexProperties = Object.keys(array).slice(array.length)
  if (!array.length && !nonIndexProperties.length) return `${name}[]`
  // As we know TypedArrays only contain Unsigned Integers, we can skip inspecting each one and simply
  // stylise the toString() value of them
  let output = ''
  for (let i = 0; i < array.length; i++) {
    const string = `${options.stylize(truncate(array[i], options.truncate), 'number')}${
      i === array.length - 1 ? '' : ', '
    }`
    options.truncate -= string.length
    if (array[i] !== array.length && options.truncate <= 3) {
      output += `${truncator}(${array.length - array[i] + 1})`
      break
    }
    output += string
  }
  let propertyContents = ''
  if (nonIndexProperties.length) {
    propertyContents = inspectList(
      nonIndexProperties.map(key => [key, array[key as keyof typeof array]]),
      options,
      inspectProperty as Inspect
    )
  }
  return `${name}[ ${output}${propertyContents ? `, ${propertyContents}` : ''} ]`
}