npm prefix token support

[azu]

Summary

new npm token use npm prefix.
We should support new npm token format.

npm has a new access token format | GitHub Changelog

Basic example

(IT IS DUMMY)

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

npm_     qkJaB6MffYVzZXWqmcoF49yrUxP3wf     0LsakP

prefix     Token    CRC32

Related

GitHub Token is similar approach #153

[azu]

// https://gist.github.com/kevinyan815/f71b2f5ca3541631abd2e50f3929739b
function toBase62(n) {
    if (n === 0) {
        return '0';
    }
    const digits = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
    let result = '';
    while (n > 0) {
        result = digits[n % digits.length] + result;
        n = parseInt(n / digits.length, 10);
    }
    
    return result;
}

//https://stackoverflow.com/a/18639999
const crc32 = function (str) {
    const makeCRCTable = function () {
        var c;
        var crcTable = [];
        for (var n = 0; n < 256; n++) {
            c = n;
            for (var k = 0; k < 8; k++) {
                c = ((c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
            }
            crcTable[n] = c;
        }
        return crcTable;
    };
    const crcTable = makeCRCTable();
    let crc = 0 ^ (-1);
    for (let i = 0; i < str.length; i++) {
        crc = (crc >>> 8) ^ crcTable[(crc ^ str.charCodeAt(i)) & 0xFF];
    }
    return (crc ^ (-1)) >>> 0;
};

console.log(toBase62(crc32("qkJaB6MffYVzZXWqmcoF49yrUxP3wf")).padStart(6, "0")); // "0LsakP"

minimal implementation for CRC32.
I do not know that this base62 encoding does not match upper-case and lower-case.

TODO

• npm and GitHub use same base62 table?
• Should we make it option?

Reference

• Behind GitHub's new authentication token formats | The GitHub Blog