Branches

This feature is potentially unstable. Must be used with the --unstable flag.

Dasel includes the concept of branches. branch allows you to perform one or more sub queries, with each query output as a separate document.

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Without branching

When we don't branch, the result is an array containing the items.

Given numbers.json:

{ "numbers": [{"x": 1}, {"x": 2}, {"x": 3}] }

$ cat numbers.json | dasel -i json 'numbers'
[
    {
        "x": 1
    },
    {
        "x": 2
    },
    {
        "x": 3
    }
]

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Branching on an array

When we branch, each element is output as a separate document instead of a single array.

$ cat numbers.json | dasel -i json 'branch(numbers...)'
{
    "x": 1
}
{
    "x": 2
}
{
    "x": 3
}

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Filtering branches with ignore

Since filter operates on arrays and a branch isn't technically an array, you can use ignore to exclude specific branches from the result.

$ echo '[1, 2, 3]' | dasel -i json 'branch().if ($this == 2) { ignore() } else { $this }'
1
3

Here, the element 2 is matched by the condition and ignore() removes it from the output. The remaining elements 1 and 3 are output as separate documents.

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Extracting multiple fields as separate documents

$ echo '{"name": "Tom", "age": 30, "city": "London"}' \
  | dasel -i json 'branch(name, age)'
"Tom"
30

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Notes

• branch converts an array (or multiple values) into separate output documents.

• Use the spread operator (...) to unpack an array into branch arguments.

• Use ignore to conditionally exclude branches.