flatten's Introduction

flatten

Flatten makes flat, one-dimensional maps from arbitrarily nested ones.

It turns map keys into compound names, in four default styles: dotted (a.b.1.c), path-like (a/b/1/c), Rails (a[b][1][c]), or with underscores (a_b_1_c). Alternatively, you can pass a custom style.

It takes input as either JSON strings or Go structures. It knows how to traverse these JSON types: objects/maps, arrays and scalars.

You can flatten JSON strings.

nested := `{
  "one": {
    "two": [
      "2a",
      "2b"
    ]
  },
  "side": "value"
}`

flat, err := flatten.FlattenString(nested, "", flatten.DotStyle)

// output: `{ "one.two.0": "2a", "one.two.1": "2b", "side": "value" }`

Or Go maps directly.

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

flat, err := flatten.Flatten(nested, "", flatten.RailsStyle)

// output:
// map[string]interface{}{
//  "a":    "b",
//  "c[d]": "e",
//  "c[f]": "g",
//  "z":    1.4567,
// }

Let's try a custom style, with the first example above.

emdash := flatten.SeparatorStyle{Middle: "--"}
flat, err := flatten.FlattenString(nested, "", emdash)

// output: `{ "one--two--0": "2a", "one--two--1": "2b", "side": "value" }`