aaac7fed
 liuqimichale
add
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'use strict';
// btoa polyfill for IE<10 courtesy https://github.com/davidchambers/Base64.js
var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
function E() {
this.message = 'String contains an invalid character';
}
E.prototype = new Error;
E.prototype.code = 5;
E.prototype.name = 'InvalidCharacterError';
function btoa(input) {
var str = String(input);
var output = '';
for (
// initialize result and counter
var block, charCode, idx = 0, map = chars;
// if the next str index does not exist:
// change the mapping table to "="
// check if d has no fractional digits
str.charAt(idx | 0) || (map = '=', idx % 1);
// "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
output += map.charAt(63 & block >> 8 - idx % 1 * 8)
) {
charCode = str.charCodeAt(idx += 3 / 4);
if (charCode > 0xFF) {
throw new E();
}
block = block << 8 | charCode;
}
return output;
}
module.exports = btoa;
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