JavaScript:实现将 base64 字符串转换为字节数组算法
function base64ToBuffer (b64) {
// The base64 encoding uses the following set of characters to encode any binary data as text
const base64Table = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
// Find the index of char '=' first occurrence
con