bellows

Flatten and expand golang maps and structs

Features

There are some existing golang flatten/expand implementations, but they are targeted to specific use-cases, and none of them flatten Structs. This one doesn't do Slices, but the feature could be added.

This Flatten will skip parsing a Map that does not have a String as the index.

This Flatten recursively passes values as their original Interface, so it is simpler than implementations that rely on passing reflect.Value.

Usage

// Expand a dot-separated flat map into a nested map
func Expand(value map[string]interface{}) map[string]interface{} {}

// Expand a dot-separated flat map into a nested map, with a prefix
func ExpandPrefixed(value map[string]interface{}, prefix string) map[string]interface{} {}

// Expand a dot-separated flat map into an existing nested map, with a prefix
func ExpandPrefixedToResult(value map[string]interface{}, prefix string, result map[string]interface{}) {}

// Flatten a nested map into a dot-separated flat map
func Flatten(value interface{}) map[string]interface{} {}

// Flatten a nested map into a dot-separated flat map, with a prefix
func FlattenPrefixed(value interface{}, prefix string) map[string]interface{} {}

// Flatten a nested map into an existing dot-separated flat map, with a prefix
func FlattenPrefixedToResult(value interface{}, prefix string, m map[string]interface{}) {}

Examples

Used in an update to Viper, to normalize config values coming from nested (JSON) and flat (CLI flags, env vars) sources.

Other golang flatten/expand implementations

• hashicorp/terraform/flatmap
• turtlemonvh/mapmap
• peking2/func-go
• wolfeidau/unflatten
• jeremywohl/flatten

(C) Copyright 2015 doublerebel. MIT Licensed.