README
¶
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" }`
See godoc for API.
Documentation
¶
Overview ¶
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" }`
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // Separate nested key components with dots, e.g. "a.b.1.c.d" DotStyle = SeparatorStyle{Middle: "."} // Separate with path-like slashes, e.g. a/b/1/c/d PathStyle = SeparatorStyle{Middle: "/"} // Separate ala Rails, e.g. "a[b][c][1][d]" RailsStyle = SeparatorStyle{Before: "[", After: "]"} // Separate with underscores, e.g. "a_b_1_c_d" UnderscoreStyle = SeparatorStyle{Middle: "_"} )
Default styles
var NotValidInputError = errors.New("Not a valid input: map or slice")
Nested input must be a map or slice
var NotValidJsonInputError = errors.New("Not a valid input, must be a map")
JSON nested input must be a map
Functions ¶
func Flatten ¶
func Flatten(nested map[string]interface{}, prefix string, style SeparatorStyle) (map[string]interface{}, error)
Flatten generates a flat map from a nested one. The original may include values of type map, slice and scalar, but not struct. Keys in the flat map will be a compound of descending map keys and slice iterations. The presentation of keys is set by style. A prefix is joined to each key.
func FlattenString ¶
func FlattenString(nestedstr, prefix string, style SeparatorStyle) (string, error)
FlattenString generates a flat JSON map from a nested one. Keys in the flat map will be a compound of descending map keys and slice iterations. The presentation of keys is set by style. A prefix is joined to each key.
Types ¶
type SeparatorStyle ¶
type SeparatorStyle struct {
Before string // Prepend to key
Middle string // Add between keys
After string // Append to key
}
The style of keys. If there is an input with two nested keys "f" and "g", with "f" at the root,
{ "f": { "g": ... } }
the output will be the concatenation
f{Middle}{Before}g{After}...
Any struct element may be blank. If you use Middle, you will probably leave Before & After blank, and vice-versa. See examples in flatten_test.go and the "Default styles" here.
Source Files