noldova.context.json

Reads untrusted JSON into typed values in one place. JsonReader reads an object's fields by name and type; every failure is a JsonException whose path, such as $.version, names the field that is wrong.

Install

npm install @noldova/context.json

Use

import { JsonException, JsonReader } from "@noldova/context.json";

const reader = JsonReader.parse("{\"name\":\"Fixture\",\"version\":2}");
reader.readString("name"); // "Fixture"
reader.readInteger("version"); // 2
reader.readOptionalString("detail"); // undefined: the field is absent.

try {
  reader.readString("version");
}
catch (error) {
  if (!(error instanceof JsonException))
    throw error;
  error.path; // "$.version"
}

A required field must be present and not null; an optional accessor accepts an absent field, and a nullable one accepts null. Unknown fields are ignored. The declaration file api/index.d.ts documents every member with its contract and examples.

License

MIT; see LICENSE.