Flames shot out and smoke was billowed from the building at Myrtle and Madison avenue as firefighters from several towns arrived around 11:05 p.m.
The blaze quickly reached three alarms, but was mostly knocked down as of 12:35 a.m.
Five children and 12 adults were reportedly displaced.
Companies from Irvington, Union, Montclair, Maplewood, Newark and East Orange responded.
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