业务需求，需要替换指定文件的指定数据，看目录结构需要逆UUID，找了一下引擎decodeuuid 的地方，贴出来记录一下

文件名 decode-uuid.ts

const BASE64_KEYS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

const values:number[] = new Array(123); // max char code in base64Keys

for (let i = 0; i < 123; ++i) { values[i] = 64; } // fill with placeholder('=') index

for (let i = 0; i < 64; ++i) { values[BASE64_KEYS.charCodeAt(i)] = i; }

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const HexChars = '0123456789abcdef'.split('');

const _t = ['', '', '', ''];

const UuidTemplate = _t.concat(_t, '-', _t, '-', _t, '-', _t, '-', _t, _t, _t);

const Indices = UuidTemplate.map((x, i) => (x === '-' ? NaN : i)).filter(isFinite);

export default function decodeUuid (base64: string) {

    const strs = base64.split('@');

    const uuid = strs[0];

    if (uuid.length !== 22) {

        return base64;

    }

    UuidTemplate[0] = base64[0];

    UuidTemplate[1] = base64[1];

    for (let i = 2, j = 2; i < 22; i += 2) {

        const lhs = BASE64_VALUES[base64.charCodeAt(i)];

        const rhs = BASE64_VALUES[base64.charCodeAt(i + 1)];

        UuidTemplate[Indices[j++]] = HexChars[lhs >> 2];

        UuidTemplate[Indices[j++]] = HexChars[((lhs & 3) << 2) | rhs >> 4];

        UuidTemplate[Indices[j++]] = HexChars[rhs & 0xF];

    }

    return base64.replace(uuid, UuidTemplate.join(''));

}