npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@nclsndr/visit-json-tree

v0.0.1

Published

Asynchronously visit a JSON tree based on pattern matching

Downloads

3

Readme

Visit JSON tree

Asynchronously visit a JSON tree based on pattern matching

Abstract

This library aims to provide utility functions to visit a JSON tree based on declared patterns, leveraging the async generator API.

⚠️ This is an experimental library – the API will likely change in the future.

Usage

Use cases

  • JSON tree traversal: you can use this library to traverse a JSON tree. The library will visit the tree and call the callback for each match (or entry if no patterns provided). You can then use the callback to accumulate the match.

  • JSON tree transformation: you can use this library to transform a JSON tree. The library will visit the tree and call the callback for each match. You can then use the callback to transform and accumulate the match.

  • JSON Schema validation: you can use this library to validate a JSON tree against a JSON schema. The library will visit the tree and call the callback for each match. You can then use the callback to validate the match against the schema.

Installation

via npm

npm install @nclsndr/visit-json-tree

via yarn

yarn add @nclsndr/visit-json-tree

API

visitJSONTree

Signature:


async function visitJSONTree(
  tree: unknown,
  callback: (payload: {
    path: string[];
    value: JSONValue; // inferred from the match functions
    matchedPattern: string | Symbol; // defaults to typeof LITERAL
  }) => Promise<void>,
  patterns: {
    name: string;
    match: (value: JSONValue) => Promise<{
        hasMatched: true;
        payload: JSONValue;
        isFinalMatch: boolean;
      } | {
        hasMatched: false;
    }>;
  }[]
): Promise<void>

Example:


const givenTree = { a: 1, b: { c: "2" } }
const acc: any[] = [];
await visitJSONTree(
  givenTree,
  async (match) => { // the callback is called for each match
    acc.push(match);
    match.value;
  },
  [ // the patterns are used to match against each structure of the tree
    {
      name: "is object with a",
      match: async (value) => {
        if (
          value === null ||
          typeof value !== "object" ||
          Array.isArray(value)
        ) {
          return { hasMatched: false };
        }
        if (!value.a) {
          return { hasMatched: false };
        }
        return { hasMatched: true, payload: value, isFinalMatch: false };
      },
    },
    {
      name: "is number",
      match: async (value) => {
        if (typeof value !== "number") {
          return { hasMatched: false };
        }
        return { hasMatched: true, payload: value, isFinalMatch: true };
      },
    },
    {
      name: "is object",
      match: async (value) => {
        if (
          value === null ||
          typeof value !== "object" ||
          Array.isArray(value)
        ) {
          return { hasMatched: false };
        }
        return { hasMatched: true, payload: value, isFinalMatch: true };
      },
    },
  ]
);

expect(acc[0]).toStrictEqual({
  path: [],
  value: { a: 1, b: { c: "2" } },
  matchedPattern: "is object with a",
});
expect(acc[1]).toStrictEqual({
  path: ["a"],
  value: 1,
  matchedPattern: "is number",
});
expect(acc[2]).toStrictEqual({
  path: ["b"],
  value: { c: "2" },
  matchedPattern: "is object",
});
expect(acc).toHaveLength(3);

makeVisitTreeGenerator

signature:

declare async function* makeVisitTreeGenerator(
  tree: JSONValue,
  patterns: Pattern[] | undefined,
  path: TreePath = []
): AsyncGenerator<{
  path: TreePath;
  matchedPattern: string | Symbol;
  value: Value;
}>