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Large-scale solar eruptions often include ejection of a filament, a solar flare, and expulsion of a coronal mass ejection (CME). Unravelling the magnetic processes that build up the free energy for these eruptions and trigger that energy's release in the eruption is a continuing challenge in solar physics. Such large-scale eruptions are comparatively infrequent, with the moderate level ones (say, GOES M-class events) occurring perhaps once every few days on average during active-activity times, and much less frequently during quieter times. In contrast, solar coronal jets, which are long (~50,000 km), narrow (<~10,000 km), transient (~10---20 min) plasma spires with bright bases and that are seen in soft X-rays and EUV, occur much more frequently, likely several hundred times per day independent of large-scale solar activity level. Recent studies indicate that coronal jets are small-scale versions of large-scale eruptions, often produced by eruption of a small-scale "miniflament," that results in a "miniflare" analogous to a larger typical solar flare, and that sometimes produces a CME analogue (a "narrow CME" or "white-light jet"). Under the assumption that jets are small-scale eruptions, their higher occurrence frequency and faster build-up evolution reveals perhaps fundamental aspects of all eruptions that are not as easy to discern in the more-complex magnetic environment and the slower build up to the larger eruptions. Therefore, the study of coronal jets can provide insights into the onset mechanism of CME-producing large-scale eruptions.