覆盖节点服务器中的文件

因此，在将文件上传到数据库之前，我有一台服务器将文件临时保存在其内存中。这是我的代码：

uploadImage(file, uid, res) {
    var fs = require('fs');
    mongoose.connect(config.db, {useNewUrlParser: true},).catch(e => console.log(e));
    var conn = mongoose.connection;
    Grid.mongo = mongoose.mongo;
    const gfs = Grid(conn.db);
    const writeStream = gfs.createWriteStream({
        filename: file.filename,
    });
    fs.createReadStream(file.path).pipe(writeStream);
    writeStream.on('close', file => {
        const {_id} = file;
        return Account.findByIdAndUpdate(uid, {'employer.logo': _id}).then(() => res.redirect('/employer')).catch(e => console.log(e));
    });
},

我正在尝试优化图像，然后将其上传到数据库，如下所示：

async uploadImage(file, uid, res) {
    const imagemin = require('imagemin');
    const imageminJpegtran = require('imagemin-jpegtran');
    const imageminPngquant = require('imagemin-pngquant');
    console.log(1);
    // const newFilePath = `${file.path}optimized`;
    const newFile = await imagemin([file.path], file.path, {
        plugins: [
            imageminJpegtran(),
            imageminPngquant({quality: '65-80'})
        ]
    });
    // newFile.path = newFilePath;
    console.log(2);
    console.log(file);
    console.log(newFile);
    var fs = require('fs');
    await mongoose.connect(config.db, {useNewUrlParser: true},).catch(e => console.log(e));
    var conn = mongoose.connection;
    Grid.mongo = mongoose.mongo;
    const gfs = Grid(conn.db);
    const writeStream = gfs.createWriteStream({
        filename: newFile.filename,
    });
    fs.createReadStream(newFile.path).pipe(writeStream);
    writeStream.on('close', file => {
        const {_id} = file;
        return Account.findByIdAndUpdate(uid, {'employer.logo': _id}).then(() => res.redirect('/employer')).catch(e => console.log(e));
    });
},

但这告诉我EEXIST: file already exists, mkdir '/home/alex/Documents/Projects/ontario-job-portal/public/images/logos/b80872b65d18d09bb498abcabe2f3f94'，这是真的。我正在尝试覆盖之前的图像。

我如何使其覆盖文件？

创建新文件会导致权限被拒绝错误。

编辑。重要

事实证明，imagemin函数返回的对象与前一个对象略有不同。这是我的工作代码：

async uploadImage(file, uid, res) {
    const imagemin = require('imagemin');
    const imageminJpegtran = require('imagemin-jpegtran');
    const imageminPngquant = require('imagemin-pngquant');
    console.log(1);
    const path = require("path");
    const newFilePath = path.dirname(file.path);
    const newFile = await imagemin([file.path], path.dirname(file.path), {
        plugins: [
            imageminJpegtran(),
            imageminPngquant({quality: '65-80'})
        ]
    });
    newFile.path = newFilePath;
    newFile.filename = newFile[0].path.replace(/public\/images\/logos\//, '');
    console.log(newFile.filename);
    var fs = require('fs');
    await mongoose.connect(config.db, {useNewUrlParser: true},).catch(e => console.log(e));
    var conn = mongoose.connection;
    Grid.mongo = mongoose.mongo;
    const gfs = Grid(conn.db);
    console.log(2);
    const writeStream = gfs.createWriteStream({
        filename: newFile[0].filename,
    });
    console.log(3);
    fs.createReadStream(newFile[0].path).pipe(writeStream);
    console.log(4);
    writeStream.on('close', file => {
        console.log(5);
        const {_id} = file;
        return Account.findByIdAndUpdate(uid, {'employer.logo': _id}).then(() => res.redirect('/employer')).catch(e => console.log(e));
    });
},