Forward all files as modules from a directory

forward.js

/*
It's often we have a bunch of modules that we need to just forward
from a single entry point

as following:
-- src
---- utils
------ isFunction.js
------ isString.js
------ isArray.js

Sometimes we need to create a single centeric entry point that groups all the modules as 'utils'
so that we can use it as following

const { isFunction, isArray } = require('./utils');

To do so, we have to create 'utils/index.js' and manually export a one-to-one map
as following:
module.exports = {
  isFunction: require('./isFunction'),
  isString: require('./isString'),
  isArray: require('./isArray'),
};

When we create a new util function, we have to manually add it in the index.js
What this following script does that it constructs this mapping automatically in run-time
*/

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

module.exports = (basePath) => {
  return fs
    .readdirSync(basePath) // read all files in the directory
    .map(file => file.replace('.js', '')) // remove the file extention
    .filter(file => file !== '*' && file !== 'index') // exclude '*.js' and 'index.js'
    .reduce((exports_, module_) => { // construct the map
      const modulePath = path.join(basePath, module_);
      exports_[module_] = require(modulePath);
      return exports_;
    }, {});
};

index.js

module.exports = require('path-to-forward.js')(__dirname);

/*
this is exactly equivelent to:
module.exports = {
  a: require('./a'),
  b: require('./b'),
  c: require('./c'),
  d: require('./d'),
  e: require('./e'),
  ...
}
*/