Frage im Vorstellungsgespräch bei Wissen Infotech

all basic java script questions they ask .you must do all java script array for it. 1. input : thisIsATest output : This_Is_A_Test 2. input - [1, [2], [3 , [4, null, 'str']]] output - [1,2,3,4, null, 'str']