Node Config with modules

This repo is to demo node-config and how errors occur when the module references the config by config.get('myModule.apple') rather than dot notation config.myModule.apple.

Setup

yarn install

Error when using config.get('myModule.apple')

If you run yarn test you will notice the following error:

› yarn test
yarn run v1.22.19
$ jest
  console.log
    my config: Config { myModule: { apple: 'test-apple', pear: 'test-pear' } }

      at log (src/my-module.js:12:11)

  console.log
    apple (config.get()): test-apple

      at log (src/my-module.js:19:11)

  console.log
    pear (config.get()): test-pear

      at log (src/my-module.js:22:11)

  console.log
    my config: Config { myModule: { apple: 'test-apple', pear: 'test-pear' } }

      at log (src/my-module.js:12:11)

 FAIL  src/my-module.test.js
  my-module
    ✕ should not fail when creating multiple instances (16 ms)

  ● my-module › should not fail when creating multiple instances

    TypeError: Cannot redefine property: myModule
        at Function.defineProperty (<anonymous>)

      16 |   // result in an error on the second instantiation of the module.
      17 |   //
    > 18 |   const apple = config.get('myModule.apple');
         |                        ^
      19 |   console.log('apple (config.get()):', apple);
      20 |
      21 |   const pear = config.get('myModule.pear');

      at Config.Object.<anonymous>.util.makeImmutable (node_modules/config/lib/config.js:423:14)
      at Config.Object.<anonymous>.Config.get (node_modules/config/lib/config.js:170:12)
      at get (src/my-module.js:18:24)
      at Object.myModule (src/my-module.test.js:19:21)

This seems to occur when a second instance of myModule is created, node-config tries to set the module defaults and then deeper within that module, it tries to get a value from the config with the get method. This issue does not occur with the dot notation.

---

To confirm this, you can also call node src/index.js and the following error will occur:

› node src/index.js
my config: Config { myModule: { apple: 'default-apple', pear: 'default-pear' } }
apple (config.get()): default-apple
pear (config.get()): default-pear
my config: Config { myModule: { apple: 'default-apple', pear: 'default-pear' } }
/Users/example/config-module-example/node_modules/config/lib/config.js:423
      Object.defineProperty(object, propertyName, {
             ^

TypeError: Cannot redefine property: myModule
    at Function.defineProperty (<anonymous>)
    at Config.util.makeImmutable (/Users/example/config-module-example/node_modules/config/lib/config.js:423:14)
    at Config.get (/Users/example/config-module-example/node_modules/config/lib/config.js:170:12)
    at myModule (/Users/example/config-module-example/src/my-module.js:18:24)
    at Object.<anonymous> (/Users/example/config-module-example/src/index.js:7:1)
    at Module._compile (node:internal/modules/cjs/loader:1105:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:77:12)

Works fine with dot notation config.myModule.apple

However if I change the interals of the myModule to use dot notation when getting it's config everything works fine.

yarn test returns:

› yarn test
yarn run v1.22.19
$ jest
  console.log
    my config: Config { myModule: { apple: 'test-apple', pear: 'test-pear' } }

      at log (src/my-module.js:12:11)

  console.log
    apple (dot notation): test-apple

      at log (src/my-module.js:28:11)

  console.log
    pear (dot notation): test-pear

      at log (src/my-module.js:31:11)

  console.log
    my config: Config { myModule: { apple: 'test-apple', pear: 'test-pear' } }

      at log (src/my-module.js:12:11)

  console.log
    apple (dot notation): test-apple

      at log (src/my-module.js:28:11)

  console.log
    pear (dot notation): test-pear

      at log (src/my-module.js:31:11)

 PASS  src/my-module.test.js
  my-module
    ✓ should not fail 1 (11 ms)
    ✓ should not fail 2 (2 ms)

And node src/index.js returns:

› node src/index.js
my config: Config { myModule: { apple: 'default-apple', pear: 'default-pear' } }
apple (dot notation): default-apple
pear (dot notation): default-pear
my config: Config { myModule: { apple: 'default-apple', pear: 'default-pear' } }
apple (dot notation): default-apple
pear (dot notation): default-pear