Angular 6: saving data to local storage

Question

I have a data table which display data from external API, I want the number of items /element on the table page should be saved in local storage

Here is what I have tried so far:

 ngOnInit() {   this.moviesService.getPopularTVShows().subscribe(res => {     this.dataSource = new MatTableDataSource(res.results);     this.dataSource.paginator = this.paginator;     this.dataSource.sort = this.sort;     localStorage.setItem(this.dataSource, this.dataSource.length);     console.log(localStorage.length);   }); } 

When I run my app, the console displays undefined

What is wrong with my code? any help or suggestion is welcomed, newbie trying new stuff.

Answer 1

You should define a key name while storing data to local storage which should be a string and value should be a string

 localStorage.setItem('dataSource', this.dataSource.length); 

and to print, you should use getItem

console.log(localStorage.getItem('dataSource')); 

Answer 2

you can use localStorage for storing the json data:

the example is given below:-

let JSONDatas = [     {"id": "Open"},     {"id": "OpenNew", "label": "Open New"},     {"id": "ZoomIn", "label": "Zoom In"},     {"id": "ZoomOut", "label": "Zoom Out"},     {"id": "Find", "label": "Find..."},     {"id": "FindAgain", "label": "Find Again"},     {"id": "Copy"},     {"id": "CopyAgain", "label": "Copy Again"},     {"id": "CopySVG", "label": "Copy SVG"},     {"id": "ViewSVG", "label": "View SVG"} ]  localStorage.setItem("datas", JSON.stringify(JSONDatas));  let data = JSON.parse(localStorage.getItem("datas"));  console.log(data);