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Flatten/unflatten nested map or JSON object in Golang
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flat_test.go opts for Flatten is an pointer Jan 20, 2019
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README.md

flat Build Status

Take a golang map and flatten it or unfatten a map with delimited key.

This work inspired by the nodejs flat package

Method

Flatten

Flatten given map, returns a map one level deep.

in := map[string]interface{}{
    "a": "b",
    "c": map[string]interface{}{
        "d": "e",
        "f": "g",
    },
    "z": [2, 1.4567],
}

out, err := flat.Flatten(in, nil)
// out = map[string]interface{}{
//     "a": "b",
//     "c.d": "e",
//     "c.f": "g",
//     "z.0": 2,
//     "z.1": 1.4567,
// }

Unflatten

Since there is flatten, flat should have unfatten.

in := map[string]interface{}{
    "foo.bar": map[string]interface{}{"t": 123},
    "foo":     map[string]interface{}{"k": 456},
}

out, err := flat.Unflatten(in, nil)
// out = map[string]interface{}{
//     "foo": map[string]interface{}{
//         "bar": map[string]interface{}{
//             "t": 123,
//         },
//         "k": 456,
//     },
// }

Options

Delimiter

Use a custom delimiter for flattening/unflattening your objects. Default value is ..

in := map[string]interface{}{
   "hello": map[string]interface{}{
       "world": map[string]interface{}{
           "again": "good morning",
        }
    },
}

out, err := flat.Flatten(in, &flat.Options{
    Delimiter: ":",
})
// out = map[string]interface{}{
//     "hello:world:again": "good morning",
// }

Safe

When Safe is true, fatten will preserve arrays and their contents. Default Safe value is false.

in := map[string]interface{}{
    "hello": map[string]interface{}{
        "world": []interface{}{
            "one",
            "two",
        }
   },
}

out, err := flat.Flatten(in, &flat.Options{
    Delimiter: ".",
    Safe:      true,
})
// out = map[string]interface{}{
//     "hello.world": []interface{}{"one", "two"},
// }

MaxDepth

MaxDepth is the maximum number of nested objects to flatten. MaxDepth can be any integer number. MaxDepth = 0 means no limit.

Default MaxDepth value is 0.

in := map[string]interface{}{
    "hello": map[string]interface{}{
        "world": []interface{}{
            "again": "good morning",
        }
   },
}

out, err := flat.Flatten(in, &flat.Options{
    Delimiter: ".",
    MaxDepth:  2,
})
// out = map[string]interface{}{
//     "hello.world": map[string]interface{}{"again": "good morning"},
// }

Todos

  • Safe option for Unflatten
  • Overwrite
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