Passing Typescript "Map" as a part of Angular4 HTTP POST request

Question

I have an Angular 4 Project where I am creating a sample Map as follows:

let sampleMap = new Map<string, string>();
sampleMap.set('key1','value1');

Now I am passing this Map as a parameter to a Angular 4 Post method which connects to a Spring Boot Rest backend as follows

Angular 4 Code:

this.http.post('http://localhost:8080/data/posturl', sampleMap).map((response: Response) => {
      return <string>response.text();
    })

Spring Boot Rest Backend Code:

@RequestMapping("/posturl")
public String launch(@RequestBody Map<String, String> sampleMap) {
    System.out.println("Received=" + sampleMap);
    return "SUCCESS";
}

Although when I try to print the 'sampleMap' as shown above, it print a blank map like follows:

Received={}

I am using Typescript version '~2.3.3' and my 'tsconfig.json' mentions target as 'es5'. Can someone please explain this behavior?

Answer 1

You have to convert the Map to an array of key-value pairs, as Typescript maps cannot be used directly inside a http post body.

You can convert the map as follows:

const convMap = {};
sampleMap.forEach((val: string, key: string) => {
  convMap[key] = val;
});
this.http.post('http://localhost:8080/data/posturl', convMap).map((response: Response) => {
  return <string>response.text();
})