I updated my project and everything was fine in Angular 2 and now 4. I now brought in Angular-CLI 1.0.0 and it will not find the json file for primeNG.

 constructor(private http: Http) {}

    getFiles() {
        return this.http.get('mock_data/data.json')
            .toPromise()
            .then(res => <TreeNode[]> res.json().data)
            .then(data => { return data; });
    }

Is throwing the error and I tried adding a ./ copied the path of the folder to double check.

In my index.html file I have <base href="/"> and the directory is under src

Error:

core.es5.js:1084 ERROR Error: Uncaught (in promise): Response with status: 404 Not Found for URL: http://localhost:4200/mock_data/data.json