_.merge array-index merging in lodash 4.17.x and object-assignment compatibility boundary
The goal is to combine layered configuration objects with lodash 4.17.x _.merge while keeping array values predictable across environments. _.merge recursively merges own and inherited enumerable string-keyed properties of source objects into the destination. In lodash 4.x, arrays at the same path are merged by index rather than concatenated or replaced atom
lodash