Trying to string together fetching promises

controller.js

import {fetchHistoryData} from '/service'

function initChart(config = this.defaultConfig){
	fetchHistoryData()
		.then((response)=> {
			buildChart();
		}).catch(()=>{
		console.error('Could not get chart data.');
	});
}
}

fetchutils.js

function fetchData(url, options = {mode: 'cors'}, formatter = ((data)=>data)){
	console.log(url);
	return window.fetch(url, options)
		.then(status)
		.then(formatter)
		.then(function(data){
			return data;
		})
		.catch(throwError);
}

service.js

import {fetchData} from './fetchUtils'

export function fetchHistoryData(){
	return Promise.all([fetchHistory('set1'), fetchHistory('set2')]);
		//.then((result)=>result); ??
}

function fetchHistory(name){
	return new Promise((resolve)=>{
		const url = createHistoryUrl(name);
		resolve (fetchData(url, {mode:'no-cors'}, historyFormatter));
	});
}