Tengo una plantilla de lista como esta

 list = [ { id: "G1", text: "Group 1", idparent: "", children: [ { start: "2014-10-01", end: "2014-10-03", id: "1", text: "Task 1" idparent: "G1", }, { start: "2014-10-03", end: "2014-10-05", id: "2", text: "Task 2" idparent: "G1", } ] }, { start: "2014-10-01", end: "2014-10-03", id: "3", text: "Task 3" idparent: "", }, ];

El primer elemento con niños es un grupo de elementos y el último es un solo elemento. Y la lista a tratar es la siguiente

 list_to_tree = [ { start: "2014-10-01", end: "2014-10-03", id: "G1", text: "Group 1" id_parent: "" }, { start: "2014-10-01", end: "2014-10-03", id: "1", text: "Task 1" id_parent: "G1" }, { start: "2014-10-01", end: "2014-10-03", id: "2", text: "Task 2", id_parent: "G1" }, { start: "2014-10-01", end: "2014-10-03", id: "3", text: "Task 3" id_parent: "" }, { start: "2014-10-01", end: "2014-10-03", id: "G2", text: "Group 2" id_parent: "G1" }, { start: "2014-10-01", end: "2014-10-03", id: "4", text: "Task 4", id_parent: "G2" }, { start: "2014-10-01", end: "2014-10-03", id: "5", text: "Task 5", id_parent: "" }, { start: "2014-10-01", end: "2014-10-03", id: "G3", text: "Group 3", id_parent: "" }, ];

Cómo ordenar esta lista para que se vea como el modelo anterior sabiendo que podemos tener un número infinito de puntos secundarios (grupo o elemento). Por ejemplo: Tarea -> subtareas -> n(subtareas) si tiene