nodejs模块之文件输出md5戳

crypto是nodejs自带模块，无需安装，直接使用即可。
以下代码执行完会计算出hash值并输出 config.json 文件，

const crypto = require('crypto');
const fs = require('fs');

let computedHex = () => {
    let rs = fs.createReadStream('./' + zipName);
    let hash = crypto.createHash('md5');
    let hex

    rs.on('data', hash.update.bind(hash));

    rs.on('end', function() {
        hex = hash.digest('hex')
        console.log('hex is ' + hex);
        output(hex);
    });
}

let output = (hex) => {
    let arr = [];
    let json = {
        "name": "flyme.5.0_uc_h5.zip",
        "md5": hex,
        "lastmodify": new Date().getTime()
    };
    arr.push(json);
    fs.writeFile('./config.json', JSON.stringify(arr), function(err) {
        if (err) throw err;
        console.log('saved config.json successfully');
    });
}

zipper.zip("output/release", function(error, zipped) {

    if (!error) {
        zipped.compress(); // compress before exporting

        var buff = zipped.memory(); // get the zipped file as a Buffer
        // or save the zipped file to disk
        zipped.save("./" + zipName, function(error) {
            if (!error) {
                console.log("Ziped files successfully !");
                computedHex();
            }
        });
    } else {
        console.log(error)
    }
});