Making a POST request to SharePoint from an SPFx webpart

spfxPOST.ts

private _makePOSTRequest(): void {

    const spOpts: ISPHttpClientOptions = {
      body: `{ Title: 'Developer Workbench', BaseTemplate: 100 }`
    };

    this.context.spHttpClient.post(`${this.context.pageContext.web.absoluteUrl}/_api/web/lists`, SPHttpClient.configurations.v1, spOpts)
      .then((response: SPHttpClientResponse) => {
        // Access properties of the response object. 
        console.log(`Status code: ${response.status}`);
        console.log(`Status text: ${response.statusText}`);

        //response.json() returns a promise so you get access to the json in the resolve callback.
        response.json().then((responseJSON: JSON) => {
          console.log(responseJSON);
        });
      });
}