typescript - Enable Access-Control-Allow-Origin in angular 5 from Client side

I am using httpClient angular package for get requests. I am using https://api.independentreserve.com/Public/GetValidPrimaryCurrencyCodes url for fetching data. It is giving CORS error in console.

I don't have access to server side code, but still I want to enalbe CORS in angular service. This is my service function

myfunction() {
  let head = new HttpHeaders();
  head.append('Access-Control-Allow-Headers', 'Content-Type');
  head.append('Access-Control-Allow-Methods', 'GET');

  head.append('Access-Control-Allow-Origin', '*');
  return this.http.get("https://api.independentreserve.com/Public/GetValidPrimaryCurrencyCodes", {headers: head}).toPromise();
}

I have tried it with chrome cors extension, and it works fine. But I want this to be enabled from angular code.

I have also tried working with proxies, following tutorial. BUt it is still not working. This is my object in proxy.conf.json file.

{

  "/api": {
    "target": "https://www.independentreserve.com/Public/GetValidPrimaryCurrencyCodes",
    "secure": false
  },
  "changeOrigin": true
}

and added "start": "ng serve --proxy-config proxy.conf.json" in package.json file. It is not working this way either.

Can any body give me some solution?