Dot

Simple get/set with dot-notation for Go that can operate on maps, structs and interfaces.

Usage

Get

Get will retrieve the value at the specified dot path. It will return an error if the property is not found.

sample := SampleStruct{
    A: SampleStructA{
        Text: "foo",
    },
    B: 8,
    C: "something",
}

// nested get, make "a" lowercase to demonstrate case-insensitivity
aText, err := Get(sample, "a.text")
if err != nil {
    // handle the error
}

// aText will be equal to "foo"

sampleMap := make(map[string]interface{})
sampleMap["D"] = "onmap"

dText, err := Get(sampleMap, "D")
if err != nil {
    // handle the error
}

// dText will be "onmap"

A fallback mechanism is also available, in which you define a list of properties and the first property with a value will be used for the Get function.

sample := SampleStruct{
    A: 0.65,
    B: 8,
    C: "something",
}

// nested get, make "a" lowercase to demonstrate case-insensitivity
fallbackText, err := dot.Get(sample, "x", "y", "b")
if err != nil {
    // handle the error
}

// fallbackText will be equal to 8

Set

Sets the value at the dot-property provided. Will create map[string]interface{} for any missing levels along the way. If that poses an issue (struct setting, perhaps), it's recommended to allocate structures accordingly.

obj := make(map[string]interface{})
err := dot.Set(obj, "X", "test34")
if err != nil {
	// handle err
}

// obj.X will be "test34"

Keys

Gets the list of keys for an arbitrary structure (non-recursively). In the result below, the result will be ["A", "B"], though it's best to not assume the elements are ordered:

testStruct := TestStruct{
    A: false,
    B: map[string]interface{}{
        "A": 1,
    }
}

keysFromStruct := dot.Keys(testStruct)

Extend

Writes any non-nil, non-default value from the right object to the left object.

TODO: example needed

KeysRecursive

Just like Keys, only recursive

KeysRecursiveLeaves

Just like KeysRecursive, except it returns only items with no "children"

Additional Getters (TODO: Enhance Details)

• GetString
• GetInt64
• GetFloat64

Notable details:

• Property access is case-insensitive
• Failure to find a value at the provided property with Get will result in an error (you can still choose to ignore the error and count on a nil value, if you wish)

Common Errors

object must be a pointer to a struct

This error means that you're passing a struct to dot.Set, when you should be passing a pointer to the struct. Add a & before the struct you're passing.