Problem: Determine all the paths for a given node.

paths.coffee

# Problem: Determine all the paths for a given node.
#
#           A
#          / \
#         /   \
#        B     C
#       / \     \
#      /   \     \
#     C     D     D
#      \
#       \
#        D

A = name: 'A', parents: []
B = name: 'B', parents: [A]
C = name: 'C', parents: [A,B]
D = name: 'D', parents: [B,C]

paths = ({name, parents}, memo = [], results = []) ->
  memo = [name, memo...]
  if parents.length
    paths parent, memo, results for parent in parents
  else
    results.push memo
  results

# > console.log paths A
# [ [ 'A' ] ]
# > console.log paths B
# [ [ 'A', 'B' ] ]
# > console.log paths C
# [ [ 'A', 'C' ], [ 'A', 'B', 'C' ] ]
# > console.log paths D
# [ [ 'A', 'B', 'D' ], [ 'A', 'C', 'D' ], [ 'A', 'B', 'C', 'D' ] ]

Nice!