避免回调地狱 [英] Avoiding callback hell

问题描述

我有这段代码可为"./markdown"文件夹中的每个markdown文件提供服务.在"/api/markdown/文件名"中.

I have this code that serves every markdown file in the './markdown' folder. At '/api/markdown/filename'.

var apiRouter = express.Router();

markdownFolder = './markdown/';

apiRouter.get('/:markdown_file_noext', function(req, res) {
        fs.readdir(markdownFolder, function(err, markdown) {
            if (err) throw err;
            markdown.forEach(function(file) {
            fs.readFile(markdownFolder + file, 'utf8', function(err, file_content) {
                if (err) throw err;
                fileNoExtension = file.slice(0, file.indexOf('.'));

                if (req.params.markdown_file_noext == fileNoExtension) {
                    res.json({ 
                        'title': fileNoExtension,
                        'markdown': marked(file_content)
                    });
                };
            });
        });
    });
});

但是我最终拥有大量的回调来实现'fs'方法的本质.我如何避免这种情况?

But i end having a ton of callbacks do the the nature of the 'fs' methods. How do i avoid this?

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