"There are multiple modules with names that only differ in casing"

[dyh333]

i cloned one project to local and npm install, npm start. but found below warning.
my dev environment is in windows 10 system

WARNING in (webpack)/buildin/module.js
There are multiple modules with names that only differ in casing.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Use equal casing. Compare these module identifiers:

• E:\GitHub\angular2-webpack-starter\node_modules\webpack\buildin\module.js
  Used by 2 module(s), i. e.
  E:\GitHub\angular2-webpack-starter\node_modules\punycode\punycode.js
• e:\GitHub\angular2-webpack-starter\node_modules\webpack\buildin\module.js
  Used by 1 module(s), i. e.
  e:\GitHub\angular2-webpack-starter\node_modules\rxjs\util\root.js

[inska]

Same here

[junyun0516]

me too ㅠㅠ

[Junik]

If u use VS Code try change path to project from
c:[path to angular2-webpack-starter]
to
C:[path to angular2-webpack-starter]

in @dyh333 case fix:
e:\GitHub\angular2-webpack-starter> cd E:\GitHub\angular2-webpack-starter
npm start
in your terminal or cli

[PatrickJS]

/\ this is an OS (windows) problem. Please see the solution above via @Junik

[alvipeo]

@gdi2290 well, there are lots of us...

[PatrickJS]

this is a problem with node.js and windows so I can't do anything about it. you just need to make sure you cd with the correct path

[aminebizid]

On Windows, stop naming files with upper case. Here we use kebab case

[luchillo17]

I'm having almost the same warning except it's in Mac:

WARNING in ./~/rxjs/add/operator/map.js
There are multiple modules with names that only differ in casing.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Use equal casing. Compare these module identifiers:
* /Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/string-replace-loader/index.js?{"search":"var sourceMappingUrl = extractSourceMappingUrl\\(cssText\\);","replace":"var sourceMappingUrl = \"\";","flags":"g"}!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/Rxjs/add/operator/map.js
    Used by 1 module(s), i. e.
    /Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/string-replace-loader/index.js?{"search":"var sourceMappingUrl = extractSourceMappingUrl\\(cssText\\);","replace":"var sourceMappingUrl = \"\";","flags":"g"}!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/Rxjs/Rx.js
* /Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/string-replace-loader/index.js?{"search":"var sourceMappingUrl = extractSourceMappingUrl\\(cssText\\);","replace":"var sourceMappingUrl = \"\";","flags":"g"}!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/rxjs/add/operator/map.js
    Used by 1 module(s), i. e.
    /Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/@angularclass/hmr-loader/index.js?pretty=true&prod=false!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/awesome-typescript-loader/dist/entry.js!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/angular2-template-loader/index.js!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/node_modules/string-replace-loader/index.js?{"search":"(System|SystemJS)(.*[\\n\\r]\\s*\\.|\\.)import\\((.+)\\)","replace":"$1.import($3).then(mod => (mod.__esModule && mod.default) ? mod.default : mod)","flags":"g"}!/Users/aplicaciones2/Documents/Luchillo-tech-showcase/src/vendor.browser.ts

That one error is repeated aprox 52 times with different rxjs operators.

So as this happens to me in Mac OSX 'El Capitan', i don't think my issue is with the cd used, any ideas?

Update: After some digging it happens whenever i import the Rxjs Observable, it seems the string-replace-loader used in the preLoader config in the webpack.common.js file is responsible for that issue.

[luchillo17]

Ok found my issue, i'm importing like:

import { Observable } from 'Rxjs/Observable';
import { Subscription } from 'Rxjs/Subscription';
import 'Rxjs/add/operator/debounceTime';
import 'Rxjs/add/observable/fromEvent';

When it should be like:

import { Observable } from 'rxjs/Observable';
import { Subscription } from 'rxjs/Subscription';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/observable/fromEvent';

Note the upper case R in rxjs.

[buddyackerman]

@Junik this fix didn't work for me as my path was already set with an upper case drive letter. Is the casing in the path critical as well? I have mixed case in the folders of the path to my project directory.

e.g. C:\Projects\Angular2\Blah\MyProject

[MarkPieszak]

@buddyackerman I just ran into this on one of my machines and realized I was using Node 6.4, I upgraded to 7.1 and the issues went away, could of been the way I was doing the directory as well, but I believe this has been fixed on the Node end (see nodejs/node#6624)