字符串转换为字节数组、16进制转换为base64、base64转换为字符串数组、base64转换为16进制（微信小程序）

1、字符串转换为字节数组

// 字符串转为字节数组
function stringToByteArray(str) {
  var array = new Uint8Array(str.length);
  for (var i = 0; i < str.length; i++) {
    array[i] = str.charCodeAt(i);
  }
  return array;
}

2、16进制转换为base64

// 16进制转换为base64
function HexToBase64(sha1) {
  var digits = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
  var base64_rep = ""
  var ascv
  var bit_arr = 0
  var bit_num = 0

  for (var n = 0; n < sha1.length; ++n) {
    if (sha1[n] >= 'A' && sha1[n] <= 'Z') {
      ascv = sha1.charCodeAt(n) - 55
    } else if (sha1[n] >= 'a' && sha1[n] <= 'z') {
      ascv = sha1.charCodeAt(n) - 87
    } else {
      ascv = sha1.charCodeAt(n) - 48
    }

    bit_arr = (bit_arr << 4) | ascv
    bit_num += 4
    if (bit_num >= 6) {
      bit_num -= 6

      base64_rep += digits[bit_arr >>> bit_num]
      bit_arr &= ~ (-1 << bit_num)
    }
  }

  if (bit_num > 0) {
    bit_arr <<= 6 - bit_num
    base64_rep += digits[bit_arr]
  }
  var padding = base64_rep.length % 4

  if (padding > 0) {
    for (var n = 0; n < 4 - padding; ++n) {
      base64_rep += "="
    }
  }
  return base64_rep
}

3、base64转换为字符串数组

https://www.npmjs.com/package/base64-arraybuffer

const base64ToArrayBuffer = require('base64-arraybuffer')

// base64转换为字符串数组
export function base64ToArrayBufferFn(base64) {
  return base64ToArrayBuffer.decode(base64)
}

4、base64转换为16进制（微信小程序）

// base64转为16进制
function base64ToHex(base64Str) {
  const binaryStr = weAtob(base64Str);
  // 创建一个Uint8Array来存储二进制数据
  const uint8Array = new Uint8Array(binaryStr.length);
  for (let i = 0; i < binaryStr.length; i++) {
    uint8Array[i] = binaryStr.charCodeAt(i);
  }
  // 使用toString方法将二进制数据转换为十六进制[字符串]
  let hexStr = ''
  for (let i = 0; i < uint8Array.length; i++) {
    const hex = uint8Array[i].toString(16).padStart(2, '0');
    hexStr += hex;
  }
  return hexStr;
}

5、base64转换为16进制（非小程序）

// base64转为16进制
function base64ToHex(base64Str) {
  const binaryStr = atob(base64Str);
  // 创建一个Uint8Array来存储二进制数据
  const uint8Array = new Uint8Array(binaryStr.length);
  for (let i = 0; i < binaryStr.length; i++) {
    uint8Array[i] = binaryStr.charCodeAt(i);
  }
  // 使用toString方法将二进制数据转换为十六进制[字符串]
  let hexStr = ''
  for (let i = 0; i < uint8Array.length; i++) {
    const hex = uint8Array[i].toString(16).padStart(2, '0');
    hexStr += hex;
  }
  return hexStr;
}