如何访问server.js文件之外的应用程序？

Question

I have two files:

const app = express();
require('./server/config/crawlerBasedModels.config').basedModels()
.then((models) => {
    app.locals.basedModels = models;
    console.log(app.locals.basedModels);
})
.catch(err => console.log(err));

const fs = require('fs');
const Promise = require('bluebird');
module.exports = {
basedModels: () => {
    return new Promise((res, rej) => {
        let basedModelsPath = require('../config/exportFolderPath');
        const basedModels = JSON.parse(fs.readFileSync(basedModelsPath + '/basedModels.json'));
        if(basedModels) {console.log(basedModels); return res(basedModels);}
        return rej('couldnt load basedModels file!');
    });
}
};

My question is how can I set a global var within my app that will be exposed for the entire of the app lifetime?

Answer 1

There are two ways to accomplish this.

<app.js>
const app = module.exports = express();
app.locals.test = 'test is valid';

<anotherfile.js>
const app = require('./app');
console.log(app.locals.test);

Now, anytime you require app , it will set the app.locals and it'll be accessible to you in another file.

Another way to do it is to have a separate blank file, called global.js.

<global.js>
empty file

<test1.js>
const global = require('./global');
global.test = 'setting var in test1.js';

<test2.js>
const global = require('./global');
console.log('global vars %j', global);

<node.js runtime>
> const a = require('./test1.js')
> const b = require('./test2.js');
global vars {"test":"setting var in test1.js"}

The only caveat here will be test1 has to be required before you can access the global variable. But, your use case demands that as well, setting something in app.locals and then using it somewhere else.