testlist <- list(data = c("isnavbbddinqlticntqp", "ns", NA, "ohrgystnhtujdiziqnly",  "dwvtkfvzzoccnokguwip", NA, NA, "slycgbssjilabgaglgvv", NA, "bifdh",  "nnhdeeytdcvcpdqbsres", "fdvdrnugjkbrmenikbxd", NA, "xnxpqzcmnmxn",  NA, NA, "llkvpktmolaaewly", NA, NA), ease = c("xisjibtj", "veqkrocvfljpl",  "scgtmmkuwizdofjlde", "wopusddttljfuhkpqked", NA, NA, NA, NA,  "br", "cqepafuhwflfqj", "gkfkwlnktpvuazf", NA, "auhottfuqjgjqxoyfjak",  "toovpggjxudppvtadrpe", "orikueqcidfxuqizuf", "wogvnekshxxeoguxqucq",  "qaijoupkbyslhmmelbpn", "uqirjdssgbioamcmcoyw", "cedsat", "juwwuchuakssfuslhdgt",  "ikeik", "zx", NA, "vjkoyrgxbgguhbagcdzr", "dvclieyftoxueaamxqhs",  NA, NA, "jbdbpbqshgyymmjwfm", "ztwsk", "vsewkkkpkqsipcqdhfso" ), frame = c(1890654570L, -701534351L, 814664542L, -1539186207L,  -1062532862L, -728923134L, NA, -565162417L, 23574999L, -1775744826L,  -1240193958L, 1426406166L, -1320937339L, -761493601L, 1812837450L,  1560451422L, 1766995200L, 2055063088L, -1846834201L, -255394399L,  185935581L, -1314030563L, -1171232745L, 838956443L, 1420467150L,  677576633L, 1300930621L, 1352523611L, -1308280732L, -1280016019L,  -454458090L, -335891905L, -1521676851L, -1358133508L, -1775813913L,  -1004977545L, 511433681L, 794574612L, 1187260977L, -1092849565L,  712847577L, -1967663584L, -569374814L, 692721991L, -973858316L,  1364723863L, 473155802L, 255344185L, -1251077313L, 636051459L,  -110647774L, -1312855690L, -1266521339L, -629957386L, -1503342154L,  -1676677295L, 2097320355L, NA, 1481377290L, 208699584L, -219429427L,  1600242437L, -980108447L, -1549028831L, -1388067687L, 879394189L,  -1216047165L, -199785498L, 55096162L, -1451792530L, 186896303L,  -830353285L, -980151047L, -23951691L, 371030026L, 905703480L,  1134861036L, 453073446L, 606721522L, -1415221648L, 964847928L,  351333674L, 224801858L, 1629846181L, -921398812L, 384567866L,  367013312L, -2053427009L, 496695090L, -1964745577L, 1251072684L,  -1235988097L, 1776444287L, -831669788L), group = c("qsuhgwk",  "cahwyyxmvf", "rtsaewgviggputknaunv", "bansvuushyvlzobrvkxf",  "dpteytnatxnznsqgchow", "smuwpxzavzaaiazroiqx", NA, "pxhxvsphrwgosziwpohu",  "hrvjerojzkytyodcbzya", "czfnkwkfqtjlzihedjet", "io", "ywphvwvawjlikwq",  NA, "tfklrynvjaplktclgz", NA, NA, NA, NA, "yfhakygjujzifwonnxlc",  "eqkaybzxrhiuxyerozlj", "bqwcenwloascalhacoo", "lgvypdqtctpyvijwuwvl",  "", "esifsdnqpeasirdw", "fiysxeatzsidgjnqoswq", NA, "wxweopnavjspwjaghzkj",  NA, NA, NA, "bdkjeejrftbjcykunrse", NA, NA, "amrobelckuahkbafbsbx",  "qyemvpatgptyjolrm", "m", NA, NA, "bjxwgfjrzjbekbaqslfz", "qrr",  NA, NA, "yxn", "juwvmdhqeaxoloprozlo", "bqsxkussmxsbvkqrakbu",  "nkkdbuaczumjueybrhfo", "", "wguvuequowwvsuxzenzc", "wxcsiylpqieobomojked",  "hytljrlypffttywbgede", "zvyadhziuevleojzamoh", "cdwdfvzcqi",  "edxmpbikdivssklrjflf", "x", "auwkphnndelhsi", "faiivmkozfaafhahrjkz",  "actks", NA, "iabysumninspkgsgwjos", "xhvcnjwgvjlkavokmjeu",  "pscueaphd", "jsfijtyit", "kcnaauovufy"))
result <- do.call(tweenr:::constant_element_interpolator,testlist)
str(result)