# Delete objects from an array inside an object
# https://stackoverflow.com/questions/35876490/how-to-remove-an-array-element-with-jq
del(.some_items[] | select(.this == "that"))
del(.some_items[] | select(.this != "that"))
del(.some_items[] | select(.this == null)) # works for missing stuff too

# if the array is at top level, select() works out of the box
.[] | select(.foo == "bar")  # and so on...


# keep only some keys/reshaping/generating a new object
.[] | { foo: .x.foo, bar: .there.comes.other }

# remove keys pointing to null values in all objects inside an array
# https://stackoverflow.com/questions/39500608/remove-all-null-values
.[] | del(.. | nulls)  # jq >= 1.6
.[] | with_entries( select( .value != null )
.[] | del( .[ (keys - [paths[]])[] ] )

# remove keys having a specific value, >= 1.6
.[] | del(.. | select(. == "xxx"))

# do the same up to 1.5
.[] | del(recurse(.[]?; true) | select(...))

# merge stuff together
# https://stedolan.github.io/jq/manual/#Builtinoperatorsandfunctions
.foo + .bar
# if foo and bar are arrays: concatenate
# if foo and bar are objects: merge objects (rhs wins)
# if foo and bar are strings: concatenate
# numbers work as expected

add([.foo, .bar]) # add works with arrays of stuff, apply "+" to all