node.js TypeError: Cannot read property 'substr' of undefined on start

The project has just upgraded to angular 4. The issue i am having is that when executing npm start to get the app running. It throws this error. Running on windows and the backend dev is on a mac, he is not getting the issue running the same repo but I am.

below are the results from using git bash along with 'ng -v'

thanks.

    user@DESKTOP-5134GU5 MINGW64 ~/Documents/project-dir (master)
    $ npm start

    > project-webpack@0.0.0 start C:\Users\user\Documents\project-dir
    > webpack-dev-server --port=4200

     10% building modules 2/2 modules 0 activeProject is running at http://localhost:4200/
    webpack output is served from /
    92% chunk asset optimizationC:\Users\user                            
    \Documents\project-dir\node_modules\source-map\lib\source-node.js:115
            node.add(nextLine.substr(0, mapping.generatedColumn));
                             ^

    TypeError: Cannot read property 'substr' of undefined
        at Function.<anonymous> (C:\Users\user\Documents\project-dir\node_modules\source-map\lib\source-node.js:115:26)
        at Array.forEach (native)
        at BasicSourceMapConsumer.SourceMapConsumer_eachMapping [as eachMapping] (C:\Users\user\Documents\project-dir\node_modules\source-map\lib\source-map-consumer.js:155:14)
        at Function.SourceNode_fromStringWithSourceMap [as fromStringWithSourceMap] (C:\Users\user\Documents\project-dir\node_modules\source-map\lib\source-node.js:80:24)
        at SourceMapSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\SourceMapSource.js:42:20)
        at ReplaceSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ReplaceSource.js:69:29)
        at CachedSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\CachedSource.js:12:23)
        at C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:40:49
        at Array.map (native)
        at ConcatSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:39:60)
        at C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:40:49
        at Array.map (native)
        at ConcatSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:39:60)
        at C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:40:49
        at Array.map (native)
        at ConcatSource.node (C:\Users\user\Documents\project-dir\node_modules\webpack-sources\lib\ConcatSource.js:39:60)

    npm ERR! Windows_NT 10.0.14393
    npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "start"
    npm ERR! node v7.9.0
    npm ERR! npm  v4.2.0
    npm ERR! code ELIFECYCLE
    npm ERR! errno 1
    npm ERR! project-webpack@0.0.0 start: `webpack-dev-server --port=4200`
    npm ERR! Exit status 1
    npm ERR!
    npm ERR! Failed at the project-webpack@0.0.0 start script 'webpack-dev-server --port=4200'.
    npm ERR! Make sure you have the latest version of node.js and npm installed.
    npm ERR! If you do, this is most likely a problem with the project-webpack package,
    npm ERR! not with npm itself.
    npm ERR! Tell the author that this fails on your system:
    npm ERR!     webpack-dev-server --port=4200
    npm ERR! You can get information on how to open an issue for this project with:
    npm ERR!     npm bugs project-webpack
    npm ERR! Or if that isn't available, you can get their info via:
    npm ERR!     npm owner ls project-webpack
    npm ERR! There is likely additional logging output above.

    npm ERR! Please include the following file with any support request:
    npm ERR!     C:\Users\user\AppData\Roaming\npm-cache\_logs\2017-04-22T09_57_06_315Z-debug.log

    user@DESKTOP-5134GU5 MINGW64 ~/Documents/fanagerfrontendwebpack (master)
    $ ng -v
        _                      _                 ____ _     ___
       / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
      / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
     / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
    /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                   |___/
    @angular/cli: 1.0.0 (e)
    node: 7.9.0
    os: win32 x64
    @angular/common: 4.0.1
    @angular/compiler: 4.0.1
    @angular/core: 4.0.1
    @angular/forms: 4.0.1
    @angular/http: 4.0.1
    @angular/material: 2.0.0-beta.1
    @angular/platform-browser: 4.0.1
    @angular/platform-browser-dynamic: 4.0.1
    @angular/router: 4.0.1
    @angular/cli: 1.0.0
    @angular/compiler-cli: 4.0.1

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