Merge maps with recursive nested maps in Groovy
You can write one for Map
using recursion:
Map.metaClass.addNested = { Map rhs ->
def lhs = delegate
rhs.each { k, v -> lhs[k] = lhs[k] in Map ? lhs[k].addNested(v) : v }
lhs
}
def map1 = [
"a" : "1",
"animals" : ["cat" : "blue"]
]
def map2 = [
"b" : 2,
"animals" : ["dog" : "red"]
]
assert map1.addNested( map2 ) == [
a: '1',
animals: [cat: 'blue', dog: 'red'],
b: 2
]
I had a similar solution as @dmahapatro, but with a method with variable arguments:
def m1 = [a: 1, animals: [cat: 'blue']]
def m2 = [b: 2, animals: [dog: 'red']]
Map merge(Map... maps) {
Map result
if (maps.length == 0) {
result = [:]
} else if (maps.length == 1) {
result = maps[0]
} else {
result = [:]
maps.each { map ->
map.each { k, v ->
result[k] = result[k] instanceof Map ? merge(result[k], v) : v
}
}
}
result
}
assert [:] == merge()
assert m1 == merge(m1)
assert [a:1, b:2, animals:[cat:'blue', dog:'red']] == merge(m1, m2)