Singles’ Day is the world’s biggest shopping event. In less than a decade, Alibaba Group Holding Ltd. turned a quirky celebration for unmarried young adults in China into a global extravaganza drawing in thousands of retailers and hundreds of millions of shoppers of all ages — hitched or otherwise. It’s spread to other e-commerce operators and will include more brick-and-mortar stores. The big unknown: To what extent, if any, the brewing U.S.-China trade war will cut into Singles’ Day sales.
