pure-JSON

Pure version of built-in JSON Object

JSON#parse and JSON#stringify without throwing an error and any types.

Why?

Methods of the JSON object in Built-in are not pure functions and may throw errors. Also, as of TypeScript 4.7, there is a divergence between implementation and types.

For example, JSON#stringify may return undefined for historical reasons. However, the return type is string.

JSON.stringify(undefined); // undefined

This project will resolve these. The return value returns the return value of the function and the error, as in GoLang. (But as a tuple.)

Example

JSON#parse

import { JSON } from "https://deno.land/x/pure_json@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";

const [data, err] = JSON.parse(`{ "hello": "world"}`);

assertEquals(err, undefined);
assertEquals(data, { hello: "world" });

JSON#stringify

import { JSON } from "https://deno.land/x/pure_json@$VERSION/mod.ts";
import {
  assertEquals,
  assertIsError,
} from "https://deno.land/std@$VERSION/testing/asserts.ts";

const cycle: Record<string, unknown> = {};
cycle[""] = cycle;

const [data, err] = JSON.stringify(cycle);

assertIsError(err, TypeError);
assertEquals(data, undefined);

API

JSON

An intrinsic object that provides functions to convert JavaScript values to and from the JavaScript Object Notation (JSON) format.

parse

Safe converts a JavaScript Object Notation (JSON) string into an object. It does not throw errors compared to JSON.parse.

import { parse } from "https://deno.land/x/pure_json@$VERSION/mod.ts";
import { assertEquals } from "https://deno.land/std@$VERSION/testing/asserts.ts";

const [data, err] = parse(`{ "hello": "world"}`);

assertEquals(err, undefined);
assertEquals(data, { hello: "world" });

Parameters

text: string
reviver: Parameters<typeof JSON.parse>[1]

Return Type

[data: json, err: undefined] | [data: undefined, err: SyntaxError]

stringify

Safe converts a JavaScript value to a JavaScript Object Notation (JSON) string.

import { stringify } from "https://deno.land/x/pure_json@$VERSION/mod.ts";
import {
  assertEquals,
  assertIsError,
} from "https://deno.land/std@$VERSION/testing/asserts.ts";

const cycle: Record<string, unknown> = {};
cycle[""] = cycle;

const [data, err] = stringify(cycle);

assertIsError(err, TypeError);
assertEquals(data, undefined);

Parameters

value: unknown
replacer?: (number | string)[] | null
space?: string | number

Return Type

[valid: false, error: TypeError] | [valid: true, data: string]

json

Types for JSON.

type json =
  | string
  | number
  | boolean
  | null
  | { [k: string]: json }
  | json[];

License

Released under the MIT license