如何在NodeJS中动态加载外部配置文件

Question

In a NodeJS application I would like to load configuration data (reports to be generated) from external files dynamically. I can load them statically by using require('path/config');

But I do have parts of the configuration that need to be refreshed on a regular schedule and, to make it all more complicated, these configuration files contain a function that must be executable.

One such report looks as follows:

const report = {
  name : 'Report 3',
  description : 'Very simple report.',
  // Some properties
  preprocessor : function() {
  },
  // Some more properties
};

module.exports = report;

When using require to re-load the report it is basically not reloaded. Even if I change something, it stays the same. (Reason: require() uses caching and rightfully it does.)

What is a good way (maybe an external library) to re-load external configuration files that contain executable functions?

Answer 1

I would use fs . If you have complete control over the configuration files (otherwise it's dangerous) you can use eval .

var fs = require('fs');

var file = fs.readFileSync(filename);
var module = {}
eval(file);

// You can access report in module.exports

If you don't want to block your application (usually recommended) you should use the async version and provide callbacks.

Answer 2

To circument caching problems, I now use the library require-without-cache . Seems to do the job.