二进制互转
file转base64
function fileToBase64(file) {
let reader = new FileReader()
reader.readAsDataURL(file)
return reader
}arrayBuffer转Base64
function arrayBufferToBase64 (array) {
array = new Uint8Array(array)
var length = array.byteLength
var table = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/']
var base64Str = ''
for (var i = 0; length - i >= 3; i += 3) {
var num1 = array[i]
var num2 = array[i + 1]
var num3 = array[i + 2]
base64Str += table[num1 >>> 2] +
table[((num1 & 0b11) << 4) | (num2 >>> 4)] +
table[((num2 & 0b1111) << 2) | (num3 >>> 6)] +
table[num3 & 0b111111]
}
var lastByte = length - i
if (lastByte === 1) {
var lastNum1 = array[i]
base64Str += table[lastNum1 >>> 2] + table[((lastNum1 & 0b11) << 4)] + '=='
} else if (lastByte === 2) {
var lastNum1 = array[i]
var lastNum2 = array[i + 1]
base64Str += table[lastNum1 >>> 2] +
table[((lastNum1 & 0b11) << 4) | (lastNum2 >>> 4)] +
table[(lastNum2 & 0b1111) << 2] +
'='
}
return base64Str
}