70 lines
2.5 KiB
Dart
70 lines
2.5 KiB
Dart
/// Select values in nested [List] and [Map] structures using a path that may contain wildcards.
|
|
///
|
|
/// The maps must always use [String] keys.
|
|
/// The [path] is a dot-separated list of keys and indices.
|
|
/// The wildcard "*" can be used to select all elements of a list or map.
|
|
/// The wildcard "**" can be used to select all elements of a list or map and all elements of nested lists and maps.
|
|
///
|
|
/// Returns an [Iterable] of the selected values.
|
|
///
|
|
/// Also see [selectInJsonWithPath] for a version that returns the path to the selected values.
|
|
Iterable<T> selectInJson<T>(dynamic json, String path) {
|
|
return selectInJsonWithPath<T>(json, path).map((e) => e.value);
|
|
}
|
|
|
|
/// Select values in nested [List] and [Map] structures using a path that may contain wildcards.
|
|
///
|
|
/// The maps must always use [String] keys.
|
|
/// The [path] is a dot-separated list of keys and indices.
|
|
/// The wildcard "*" can be used to select all elements of a list or map.
|
|
/// The wildcard "**" can be used to select all elements of a list or map and all elements of nested lists and maps.+
|
|
///
|
|
/// Returns an [Iterable] of the selected values and their path.
|
|
Iterable<({T value, String path})> selectInJsonWithPath<T>(
|
|
dynamic json, String path) sync* {
|
|
if (path.isEmpty) {
|
|
if (json is T) {
|
|
yield (value: json, path: "");
|
|
}
|
|
return;
|
|
}
|
|
List<String> pathParts = path.split(".");
|
|
String first = pathParts.removeAt(0);
|
|
String rest = pathParts.join(".");
|
|
({T value, String path}) addFirstToPath(({T value, String path}) element) {
|
|
return (
|
|
value: element.value,
|
|
path: element.path.isEmpty ? first : "$first.${element.path}"
|
|
);
|
|
}
|
|
|
|
if (first == "*" || first == "**") {
|
|
String continueWithPath = first == "*" ? rest : path;
|
|
if (first == "**") {
|
|
yield* selectInJsonWithPath<T>(json, rest);
|
|
}
|
|
if (json is List) {
|
|
yield* json
|
|
.expand((e) => selectInJsonWithPath<T>(e, continueWithPath))
|
|
.map(addFirstToPath);
|
|
} else if (json is Map) {
|
|
for (String key in json.keys) {
|
|
yield* selectInJsonWithPath<T>(json[key], continueWithPath)
|
|
.map(addFirstToPath);
|
|
}
|
|
}
|
|
} else if (json is List) {
|
|
try {
|
|
int index = int.parse(first);
|
|
yield* selectInJsonWithPath<T>(json[index], rest);
|
|
} catch (e) {
|
|
// The first part of the path is not an index or out of bounds -> ignore
|
|
}
|
|
} else if (json is Map) {
|
|
dynamic value = json[first];
|
|
if (value != null) {
|
|
yield* selectInJsonWithPath<T>(value, rest);
|
|
}
|
|
}
|
|
}
|