  Ultralight bosonic fields (ULBFs) are predicted by various theories beyond
the standard model of particle physics and are viable candidates of cold dark
matter. There have been increasing interests to search for the ULBFs in
physical and astronomical experiments. In this paper, we investigate the
sensitivity of several planned space-based gravitational-wave interferometers
to ultralight scalar and vector fields. Using time-delay interferometry (TDI)
to suppress the overwhelming laser frequency noise, we derive the averaged
transfer functions of different TDI combinations to scalar and vector fields,
and estimate the impacts of bosonic field's velocities. We obtain the
sensitivity curves for LISA, Taiji and TianQin, and explore their projected
constraints on the couplings between ULBFs and standard model particles,
illustrating with the ULBFs as dark matter.
