PHP's base64_decode in TypeScript

How to use

Install via yarn add locutus and import: import { base64_decode } from 'locutus/php/url/base64_decode'.

Or with CommonJS: const { base64_decode } = require('locutus/php/url/base64_decode')

Use a bundler that supports tree-shaking so you only ship the functions you actually use. Vite, webpack, Rollup, and Parcel all handle this. For server-side use this is less of a concern.

Examples

These examples are extracted from test cases that automatically verify our functions against their native counterparts.

#	code	expected result
1	base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')	'Kevin van Zonneveld'
2	base64_decode('YQ==')	'a'
3	base64_decode('4pyTIMOgIGxhIG1vZGU=')	'✓ à la mode'

Dependencies

This function uses the following Locutus functions:

• _phpRuntimeState (php/_helpers)
• _phpTypes (php/_helpers)

Here's what our current TypeScript equivalent to PHP's base64_decode looks like.

TSTypeScript JSJavaScript TSStandalone TS JSStandalone JS

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import { getPhpGlobalCallable, getPhpGlobalEntry, getPhpObjectEntry } from '../_helpers/_phpRuntimeState.ts'
import { isObjectLike, isPhpCallable } from '../_helpers/_phpTypes.ts'

export function base64_decode(encodedData: string | null | undefined): string | null | undefined {
  //  discuss at: https://locutus.io/php/base64_decode/
  // original by: Tyler Akins (https://rumkin.com)
  // improved by: Thunder.m
  // improved by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Kevin van Zonneveld (https://kvz.io)
  //    input by: Aman Gupta
  //    input by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // bugfixed by: Pellentesque Malesuada
  // bugfixed by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Indigo744
  //   example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')
  //   returns 1: 'Kevin van Zonneveld'
  //   example 2: base64_decode('YQ==')
  //   returns 2: 'a'
  //   example 3: base64_decode('4pyTIMOgIGxhIG1vZGU=')
  //   returns 3: '✓ à la mode'

  // decodeUTF8string()
  // Internal function to decode properly UTF8 string
  // Adapted from Solution #1 at https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
  const decodeUTF8string = function (str: string): string {
    // Going backwards: from bytestream, to percent-encoding, to original string.
    return decodeURIComponent(
      str
        .split('')
        .map(function (c) {
          return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
        })
        .join(''),
    )
  }

  const bufferValue = getPhpGlobalEntry('Buffer')
  if (isObjectLike(bufferValue)) {
    const bufferFrom = getPhpObjectEntry(bufferValue, 'from')
    if (isPhpCallable<[string, string], object>(bufferFrom)) {
      const decoded = bufferFrom.call(bufferValue, String(encodedData), 'base64')
      if (typeof decoded === 'object' && decoded !== null) {
        const decodedToString = getPhpObjectEntry(decoded, 'toString')
        if (isPhpCallable<[string], string>(decodedToString)) {
          const utf8Value = decodedToString.call(decoded, 'utf-8')
          if (typeof utf8Value === 'string') {
            return utf8Value
          }
        }
      }
    }
  }

  const atobValue = getPhpGlobalCallable<[string], string>('atob')
  if (atobValue) {
    const decoded = atobValue(String(encodedData))
    if (typeof decoded === 'string') {
      return decodeUTF8string(decoded)
    }
  }

  const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
  let o1: number
  let o2: number
  let o3: number
  let h1: number
  let h2: number
  let h3: number
  let h4: number
  let bits: number
  let i = 0
  let ac = 0
  let dec = ''
  const tmpArr: string[] = []

  if (!encodedData) {
    return encodedData
  }

  encodedData += ''

  do {
    // unpack four hexets into three octets using index points in b64
    h1 = b64.indexOf(encodedData.charAt(i++))
    h2 = b64.indexOf(encodedData.charAt(i++))
    h3 = b64.indexOf(encodedData.charAt(i++))
    h4 = b64.indexOf(encodedData.charAt(i++))

    bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4

    o1 = (bits >> 16) & 0xff
    o2 = (bits >> 8) & 0xff
    o3 = bits & 0xff

    if (h3 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1)
    } else if (h4 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1, o2)
    } else {
      tmpArr[ac++] = String.fromCharCode(o1, o2, o3)
    }
  } while (i < encodedData.length)

  dec = tmpArr.join('')

  return decodeUTF8string(dec.replace(/\0+$/, ''))
}

import { getPhpGlobalCallable, getPhpGlobalEntry, getPhpObjectEntry } from '../_helpers/_phpRuntimeState.ts'
import { isObjectLike, isPhpCallable } from '../_helpers/_phpTypes.ts'

export function base64_decode(encodedData) {
  //  discuss at: https://locutus.io/php/base64_decode/
  // original by: Tyler Akins (https://rumkin.com)
  // improved by: Thunder.m
  // improved by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Kevin van Zonneveld (https://kvz.io)
  //    input by: Aman Gupta
  //    input by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // bugfixed by: Pellentesque Malesuada
  // bugfixed by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Indigo744
  //   example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')
  //   returns 1: 'Kevin van Zonneveld'
  //   example 2: base64_decode('YQ==')
  //   returns 2: 'a'
  //   example 3: base64_decode('4pyTIMOgIGxhIG1vZGU=')
  //   returns 3: '✓ à la mode'

  // decodeUTF8string()
  // Internal function to decode properly UTF8 string
  // Adapted from Solution #1 at https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
  const decodeUTF8string = function (str) {
    // Going backwards: from bytestream, to percent-encoding, to original string.
    return decodeURIComponent(
      str
        .split('')
        .map(function (c) {
          return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
        })
        .join(''),
    )
  }

  const bufferValue = getPhpGlobalEntry('Buffer')
  if (isObjectLike(bufferValue)) {
    const bufferFrom = getPhpObjectEntry(bufferValue, 'from')
    if (isPhpCallable(bufferFrom)) {
      const decoded = bufferFrom.call(bufferValue, String(encodedData), 'base64')
      if (typeof decoded === 'object' && decoded !== null) {
        const decodedToString = getPhpObjectEntry(decoded, 'toString')
        if (isPhpCallable(decodedToString)) {
          const utf8Value = decodedToString.call(decoded, 'utf-8')
          if (typeof utf8Value === 'string') {
            return utf8Value
          }
        }
      }
    }
  }

  const atobValue = getPhpGlobalCallable('atob')
  if (atobValue) {
    const decoded = atobValue(String(encodedData))
    if (typeof decoded === 'string') {
      return decodeUTF8string(decoded)
    }
  }

  const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
  let o1
  let o2
  let o3
  let h1
  let h2
  let h3
  let h4
  let bits
  let i = 0
  let ac = 0
  let dec = ''
  const tmpArr = []

  if (!encodedData) {
    return encodedData
  }

  encodedData += ''

  do {
    // unpack four hexets into three octets using index points in b64
    h1 = b64.indexOf(encodedData.charAt(i++))
    h2 = b64.indexOf(encodedData.charAt(i++))
    h3 = b64.indexOf(encodedData.charAt(i++))
    h4 = b64.indexOf(encodedData.charAt(i++))

    bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4

    o1 = (bits >> 16) & 0xff
    o2 = (bits >> 8) & 0xff
    o3 = bits & 0xff

    if (h3 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1)
    } else if (h4 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1, o2)
    } else {
      tmpArr[ac++] = String.fromCharCode(o1, o2, o3)
    }
  } while (i < encodedData.length)

  dec = tmpArr.join('')

  return decodeUTF8string(dec.replace(/\0+$/, ''))
}

// php/_helpers/_phpTypes (Locutus helper dependency)
type PhpNullish = null | undefined

type PhpInput = {} | PhpNullish

type PhpList<T = PhpInput> = T[]

type PhpAssoc<T = PhpInput> = { [key: string]: T }

type PhpArrayLike<T = PhpInput> = PhpList<T> | PhpAssoc<T>

type PhpCallableArgs = PhpInput[]

type PhpCallable<TArgs extends PhpCallableArgs = PhpCallableArgs, TResult = PhpInput> = (
  ...args: TArgs
) => TResult

function isObjectLike(value: PhpInput): value is PhpArrayLike<PhpInput> {
  return typeof value === 'object' && value !== null
}

function isPhpCallable<TArgs extends PhpCallableArgs = PhpCallableArgs, TResult = PhpInput>(
  value: PhpInput,
): value is PhpCallable<TArgs, TResult> {
  return typeof value === 'function'
}

// php/_helpers/_phpRuntimeState (Locutus helper dependency)
interface LocutusRuntimeContainer {
  php?: PhpAssoc<PhpInput>
}

interface PhpGlobalProcessLike {
  env?: PhpAssoc<string | undefined>
}

interface PhpGlobalBufferLike {
  from?: (...args: PhpInput[]) => PhpInput
}

interface PhpGlobalKnownEntryMap {
  process: PhpGlobalProcessLike
  Buffer: PhpGlobalBufferLike
}

type GlobalWithLocutus = {
  $locutus?: LocutusRuntimeContainer
  [key: string]: PhpInput
}

const globalContext: GlobalWithLocutus =
  typeof window === 'object' && window !== null ? window : typeof global === 'object' && global !== null ? global : {}

function getPhpGlobalEntry<TKey extends keyof PhpGlobalKnownEntryMap>(
  key: TKey,
): PhpGlobalKnownEntryMap[TKey] | undefined

function getPhpGlobalEntry(key: string): PhpInput | undefined

function getPhpGlobalEntry(key: string): PhpInput | undefined {
  const value = globalContext[key]
  return typeof value === 'undefined' ? undefined : value
}

function getPhpGlobalCallable<TArgs extends PhpInput[] = PhpInput[], TResult = PhpInput>(
  key: string,
): PhpCallable<TArgs, TResult> | undefined {
  const value = getPhpGlobalEntry(key)
  return isPhpCallable<TArgs, TResult>(value) ? value : undefined
}

function getPhpObjectEntry(value: PhpInput, key: string): PhpInput | undefined {
  if ((typeof value !== 'object' && typeof value !== 'function') || value === null) {
    return undefined
  }

  let current: object | null = value
  while (current) {
    const descriptor = Object.getOwnPropertyDescriptor(current, key)
    if (descriptor) {
      if (typeof descriptor.get === 'function') {
        const getterValue = descriptor.get.call(value)
        return typeof getterValue === 'undefined' ? undefined : getterValue
      }
      const directValue = descriptor.value
      return typeof directValue === 'undefined' ? undefined : directValue
    }
    current = Object.getPrototypeOf(current)
  }

  return undefined
}

// php/url/base64_decode (target function module)
function base64_decode(encodedData: string | null | undefined): string | null | undefined {
  //  discuss at: https://locutus.io/php/base64_decode/
  // original by: Tyler Akins (https://rumkin.com)
  // improved by: Thunder.m
  // improved by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Kevin van Zonneveld (https://kvz.io)
  //    input by: Aman Gupta
  //    input by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // bugfixed by: Pellentesque Malesuada
  // bugfixed by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Indigo744
  //   example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')
  //   returns 1: 'Kevin van Zonneveld'
  //   example 2: base64_decode('YQ==')
  //   returns 2: 'a'
  //   example 3: base64_decode('4pyTIMOgIGxhIG1vZGU=')
  //   returns 3: '✓ à la mode'

  // decodeUTF8string()
  // Internal function to decode properly UTF8 string
  // Adapted from Solution #1 at https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
  const decodeUTF8string = function (str: string): string {
    // Going backwards: from bytestream, to percent-encoding, to original string.
    return decodeURIComponent(
      str
        .split('')
        .map(function (c) {
          return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
        })
        .join(''),
    )
  }

  const bufferValue = getPhpGlobalEntry('Buffer')
  if (isObjectLike(bufferValue)) {
    const bufferFrom = getPhpObjectEntry(bufferValue, 'from')
    if (isPhpCallable<[string, string], object>(bufferFrom)) {
      const decoded = bufferFrom.call(bufferValue, String(encodedData), 'base64')
      if (typeof decoded === 'object' && decoded !== null) {
        const decodedToString = getPhpObjectEntry(decoded, 'toString')
        if (isPhpCallable<[string], string>(decodedToString)) {
          const utf8Value = decodedToString.call(decoded, 'utf-8')
          if (typeof utf8Value === 'string') {
            return utf8Value
          }
        }
      }
    }
  }

  const atobValue = getPhpGlobalCallable<[string], string>('atob')
  if (atobValue) {
    const decoded = atobValue(String(encodedData))
    if (typeof decoded === 'string') {
      return decodeUTF8string(decoded)
    }
  }

  const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
  let o1: number
  let o2: number
  let o3: number
  let h1: number
  let h2: number
  let h3: number
  let h4: number
  let bits: number
  let i = 0
  let ac = 0
  let dec = ''
  const tmpArr: string[] = []

  if (!encodedData) {
    return encodedData
  }

  encodedData += ''

  do {
    // unpack four hexets into three octets using index points in b64
    h1 = b64.indexOf(encodedData.charAt(i++))
    h2 = b64.indexOf(encodedData.charAt(i++))
    h3 = b64.indexOf(encodedData.charAt(i++))
    h4 = b64.indexOf(encodedData.charAt(i++))

    bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4

    o1 = (bits >> 16) & 0xff
    o2 = (bits >> 8) & 0xff
    o3 = bits & 0xff

    if (h3 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1)
    } else if (h4 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1, o2)
    } else {
      tmpArr[ac++] = String.fromCharCode(o1, o2, o3)
    }
  } while (i < encodedData.length)

  dec = tmpArr.join('')

  return decodeUTF8string(dec.replace(/\0+$/, ''))
}

// php/_helpers/_phpTypes (Locutus helper dependency)
function isObjectLike(value) {
  return typeof value === 'object' && value !== null
}

function isPhpCallable(value) {
  return typeof value === 'function'
}

// php/_helpers/_phpRuntimeState (Locutus helper dependency)
const globalContext =
  typeof window === 'object' && window !== null ? window : typeof global === 'object' && global !== null ? global : {}

function getPhpGlobalEntry(key) {
  const value = globalContext[key]
  return typeof value === 'undefined' ? undefined : value
}

function getPhpGlobalCallable(key) {
  const value = getPhpGlobalEntry(key)
  return isPhpCallable(value) ? value : undefined
}

function getPhpObjectEntry(value, key) {
  if ((typeof value !== 'object' && typeof value !== 'function') || value === null) {
    return undefined
  }

  let current = value
  while (current) {
    const descriptor = Object.getOwnPropertyDescriptor(current, key)
    if (descriptor) {
      if (typeof descriptor.get === 'function') {
        const getterValue = descriptor.get.call(value)
        return typeof getterValue === 'undefined' ? undefined : getterValue
      }
      const directValue = descriptor.value
      return typeof directValue === 'undefined' ? undefined : directValue
    }
    current = Object.getPrototypeOf(current)
  }

  return undefined
}

// php/url/base64_decode (target function module)
function base64_decode(encodedData) {
  //  discuss at: https://locutus.io/php/base64_decode/
  // original by: Tyler Akins (https://rumkin.com)
  // improved by: Thunder.m
  // improved by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Kevin van Zonneveld (https://kvz.io)
  //    input by: Aman Gupta
  //    input by: Brett Zamir (https://brett-zamir.me)
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // bugfixed by: Pellentesque Malesuada
  // bugfixed by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Indigo744
  //   example 1: base64_decode('S2V2aW4gdmFuIFpvbm5ldmVsZA==')
  //   returns 1: 'Kevin van Zonneveld'
  //   example 2: base64_decode('YQ==')
  //   returns 2: 'a'
  //   example 3: base64_decode('4pyTIMOgIGxhIG1vZGU=')
  //   returns 3: '✓ à la mode'

  // decodeUTF8string()
  // Internal function to decode properly UTF8 string
  // Adapted from Solution #1 at https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding
  const decodeUTF8string = function (str) {
    // Going backwards: from bytestream, to percent-encoding, to original string.
    return decodeURIComponent(
      str
        .split('')
        .map(function (c) {
          return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
        })
        .join(''),
    )
  }

  const bufferValue = getPhpGlobalEntry('Buffer')
  if (isObjectLike(bufferValue)) {
    const bufferFrom = getPhpObjectEntry(bufferValue, 'from')
    if (isPhpCallable(bufferFrom)) {
      const decoded = bufferFrom.call(bufferValue, String(encodedData), 'base64')
      if (typeof decoded === 'object' && decoded !== null) {
        const decodedToString = getPhpObjectEntry(decoded, 'toString')
        if (isPhpCallable(decodedToString)) {
          const utf8Value = decodedToString.call(decoded, 'utf-8')
          if (typeof utf8Value === 'string') {
            return utf8Value
          }
        }
      }
    }
  }

  const atobValue = getPhpGlobalCallable('atob')
  if (atobValue) {
    const decoded = atobValue(String(encodedData))
    if (typeof decoded === 'string') {
      return decodeUTF8string(decoded)
    }
  }

  const b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
  let o1
  let o2
  let o3
  let h1
  let h2
  let h3
  let h4
  let bits
  let i = 0
  let ac = 0
  let dec = ''
  const tmpArr = []

  if (!encodedData) {
    return encodedData
  }

  encodedData += ''

  do {
    // unpack four hexets into three octets using index points in b64
    h1 = b64.indexOf(encodedData.charAt(i++))
    h2 = b64.indexOf(encodedData.charAt(i++))
    h3 = b64.indexOf(encodedData.charAt(i++))
    h4 = b64.indexOf(encodedData.charAt(i++))

    bits = (h1 << 18) | (h2 << 12) | (h3 << 6) | h4

    o1 = (bits >> 16) & 0xff
    o2 = (bits >> 8) & 0xff
    o3 = bits & 0xff

    if (h3 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1)
    } else if (h4 === 64) {
      tmpArr[ac++] = String.fromCharCode(o1, o2)
    } else {
      tmpArr[ac++] = String.fromCharCode(o1, o2, o3)
    }
  } while (i < encodedData.length)

  dec = tmpArr.join('')

  return decodeUTF8string(dec.replace(/\0+$/, ''))
}

Improve this function

Locutus is a community effort following The McDonald's Theory: we ship first iterations, hoping others will improve them. If you see something that could be better, we'd love your contribution.

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