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Description:

rfc 6901

RFC 6901 JSON Pointer #
JSON Pointer (RFC 6901) implementation in Dart.
Features:

Reads, writes, removes values
Fully implements the standard, including the - character
Can build the entire path, e.g. /foo/bar/-/baz
No external dependencies
100% test coverage

Constructing pointers #
A JSON Pointer object can be parsed from a string expression.
The expression MUST be a valid non-empty JSON Pointer expression with "/" and "~" escaped.
final pointer = JsonPointer('/foo/0/bar'); // a valid non-empty pointer
final alsoPointer = JsonPointer('/foo/-'); // a valid non-empty pointer with a special "-" reference
final emptyPointer = JsonPointer(); // an empty pointer

JsonPointer('oops'); // throws a FormatException: expression doesn't start with "/"
JsonPointer('/foo/~'); // throws a FormatException: unescaped "~"
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It can also be built from individual reference tokens. In such case, it will escape the tokens automatically.
final pointer = JsonPointer.build(['foo', '0', 'bar/']); // Makes "/foo/0/bar~1"
final longerPointer = JsonPointerSegment('-', pointer); // Makes "/foo/0/bar~1/-"
final evenLongerPointer = JsonPointerSegment('wow', longerPointer); // Makes "/foo/0/bar~1/-/wow"
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Reading and writing values #
The read() method returns the referenced value. The write() method returns a copy of the document with
the referenced value replaced by the new value.
import 'dart:convert';

import 'package:rfc_6901/rfc_6901.dart';

void main() {
const json = '{"foo": [{"bar": 42}]}';
final document = jsonDecode(json);
print('Original document: $document');

[
'/foo', // reads the array
'/foo/0', // reads the first element of the array
'/foo/0/bar', // reads 42
].forEach((expression) {
final pointer = JsonPointer(expression);
print('Pointer "$pointer" reads ${pointer.read(document)}');
});

[
'/foo/0/bar', // {foo: [{bar: banana}]}
'/foo/-', // {foo: [{bar: 42}, banana]}
'/a/b/-/c/d', // {foo: [{bar: 42}], a: {b: [{c: {d: banana}}]}}
].forEach((expression) {
final pointer = JsonPointer(expression);
final d = pointer.write(document, 'banana');
print('Add a banana at "$pointer": $d');
});
}
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