mapmap

Mapmap

It maps your maps!

WARNING: Development of this library has been suspended (3/22/2016) because other libraries seem to provide similar features in a better way. The flatmap package may still be useful for some projects.

WORK IN PROGRESS: Very limited features so far.

Quick Start

Mapmap is for doing quick transformations on map[string]interface{} and []interface{} objects in golang (the stuff you get back when parsing json).

Basic usage for shuffling around fields is as follows:

package main

import (
    "fmt"

    "github.com/turtlemonvh/mapmap"
)

func main() {

    // You need an object to map
    m := map[string]interface{}{
        "cat":        "garfield",
        "dog":        "odie",
        "friends":    []interface{}{"John"},
        "turtle":     "0",
        "57":         int64(57),
        "doesItWork": true,
    }

    // Create a slice of `Mapper`s describing transformations to run
    var mappers []*mapmap.Mapper
    mappers = append(mappers, mapmap.NewMapper("cat", "cat"))
    mappers = append(mappers, mapmap.NewMapper("turtle", "frog"))
    mappers = append(mappers, mapmap.NewMapper("friends.[0]", "myOnlyFriend"))

    // Run the tranformations
    new_map, processingErrors, err = mapmap.MapIt(m, mappers)

    fmt.Println(new_map)
}

This would result in the following value for new_map:

map[string]interface{}{
    "cat":          "garfield",
    "frog":         "0",
    "myOnlyFriend": "John",
}

Testing

go test ./...

Credits

• Built with the awesome cast library from spf13.
• Inspired by the viper library from spf13.
• Lots of source taken from the flatmap library in terraform.
  • Mostly I just manage maps with interfaces and return errors instead of panicing.

Alternatives

The following is a list of libraries that you may want to use instead of mapmap.

• https://github.com/buger/jsonparser
  • fast json parser
  • allows accessing values by path
• https://github.com/fatih/structs
  • package for working with arbitrary structs and transforming into map[string]interface{}
• https://github.com/mitchellh/mapstructure
  • package for converting between structs and arbitrary maps
  • good for json of unknown strucrure
• https://github.com/Jeffail/gabs
  • package for working with dynamic or unknown json
  • allows accessing values by path
• https://github.com/akutz/golf
  • package for listing the fields of arbitrary data types
• https://github.com/imdario/mergo
  • package for merging go structs and maps
• https://github.com/mitchellh/reflectwalk
  • package for walking complex object structures

TODO

• add transform functions
• add validators
• add type handling
• add error handling (returning array of errors) in addition to standard handling
• add benchmarks for simple transformations