Create and add if does not exist

[electriquo]

how can i make dasel to create an array and add an object to it if the object is does not exist.
for instance, giving an empty json/yaml, how to make dasel create a key named names that is an array with the object {"name": "Tom", "level": "Master"} to achieve

names:
  - name: Tom
    level: Master

yet, if the {"name": "Tom", "level": "Master"} object already exist, then do nothing.

[TomWright]

This kind of optional update doesn't really exist yet, but you should be able to combine 2 dasel commands together to get the expected outcome.

To check the presence of some item you could use this.

$ echo 'names:
  - name: Tom
    level: Master' | dasel -r yaml 'moreThan(names.all().filter(and(equal(name,Tom),equal(level,Master))).merge().len(),0)'
true
$ echo 'names:
  - name: Tom
    level: Master' | dasel -r yaml 'moreThan(names.all().filter(and(equal(name,Something),equal(level,Else))).merge().len(),0)'
false

You can then wrap this with a simple check and perform some action:

if dasel -f file.yaml 'moreThan(names.all().filter(and(equal(name,Tom),equal(level,Master))).merge().len(),0)' | grep -q 'true'
then
  echo "already exists"
else
  echo "adding"
  dasel put -f file.yaml -t json -v '{"name":"Tom","level":"Master"}' 'names.[]'
fi

[electriquo]

Any reference/guidance/example would be appreciated

[TomWright]

Hi @foolioo I've added a rough example. Note that I haven't tested this and it serves as my thought process, not necessarily a complete and working example.