jsonpath-zig

Boilerplate free, safe stdlib JSON Value access.

Provides a simple utility function to more safely access stdlib's JSON Values It let's you get a child Value from any arbitary Value by giving it a path of keys ([]const u8) and integer types, as well as the expected type for that value.

This library avoids needing to make any allocations, but note that any returned data will be tied to the lifetime of the original Value.

Usage and Examples

test "jsonpath" {
    const alloc = std.testing.allocator;
    const expectEqual = std.testing.expectEqual;
    const expectEqualSlices = std.testing.expectEqualSlices;

    const json_obj =
        \\{
        \\  "str": "string_val",
        \\  "bool": true,
        \\  "float": 0.125,
        \\  "int": 25,
        \\  "array": [
        \\    {
        \\      "some": {
        \\        "nested": {
        \\          "json": "value"
        \\        }
        \\      }
        \\    }
        \\  ]
        \\}
    ;

    const parsed_obj = try json.parseFromSlice(json.Value, alloc, json_obj, .{});
    defer parsed_obj.deinit();
    const val = parsed_obj.value;

    try expectEqual(true, try jsonPath(bool, val, .{"bool"}));
    try expectEqual(25, try jsonPath(i64, val, .{"int"}));
    try expectEqual(0.125, try jsonPath(f64, val, .{"float"}));
    try expectEqualSlices(u8, "string_val", try jsonPath([]const u8, val, .{"str"}));
    try expectEqualSlices(u8, "value", try jsonPath([]const u8, val, .{ "array", 0, "some", "nested", "json" }));
}

The "types" you can pass in are the same as the underlying types of the json.Value union. Any other type will result in a comptime error. Those types being the following (with the corresponding json.Value field)

bool (bool)
i64 (integer)
f64 (float)
[]const u8 (string)
json.Array (array)
json.ObjectMap (object)
json.Value

There is no direct way to handle null or number_string values, but you can retrieve it as a json.Value and handle the value manually.