The coronavirus pandemic has upended the U.S. economy and wreaked havoc on businesses ranging from global shipping to cruise lines to restaurants. But food-delivery companies are thriving, with DoorDash looking to be the rare winner in its niche. Since Covid-19 lockdown orders were issued across the U.S. in mid-March and consumers shifted to ordering delivery for dinner, DoorDash's sales have surged, according to data from Edison Trends, which studies anonymized and aggregated e-receipts from millions of U.S. consumers.