@saxs/json-path-transform

@saxs/json-path-transform

Transforms JSON objects using a path-based approach.

Description

This package provides a simple way to transform JSON objects using a path-based approach.

The purpose is to make it possible to write declarative transformations for json objects, hence make it useable in a configuration file or from user inputs.

Installation

Using npm

npm install @saxs/json-path-transform

Using yarn

yarn add @saxs/json-path-transform

Using pnpm

pnpm add @saxs/json-path-transform

Usage

The schema defines the transformation rules. The keys are the target keys and the values are the paths to the source keys.

import { PathTransform } from '@saxs/json-path-transform';

const schema = {
  name: '$.user.name',
  age: '$.user.age',
};

const data = {
  user: {
    name: 'John Doe',
    age: 30,
  },
};

const transformer = new PathTransform(schema).compile();

console.log(transformer(data)); // { name: 'John Doe', age: 30 }

Syntax

The JSONPath syntax is used to define the paths. The package uses the jsonpath-plus package under the hood to resolve the paths.

Exmaples can be found at https://goessner.net/articles/JsonPath/.

Root ($) key

The root key can be used to define the root of the object at any given depth. This copies the main object to that level.

import { PathTransform } from '@saxs/json-path-transform';

const schema = {
  $: '$.user',
};

const data = {
  user: {
    name: 'John Doe',
    age: 30,
  },
};

const transformer = new PathTransform(schema).compile();

console.log(transformer(data)); // { name: 'John Doe', age: 30 }

Performance

The performance is dependant on the complexity of the schema and the size of the data. The package makes a AOT compilation of the schema to make the transformation as fast as possible, and uses jsonpath-plus package under to hood to resolve results from each path.

On a M1 Macbook Air (16GB RAM) we can expect the following performance as seen under the benchmark folder.

Test Name	ops/sec	Confidence Interval
root	4,907,733	±0.20%
allAuthors	479,267	±0.35%
allAuthorsDot	1,007,505	±1.30%
addKey	449,904	±0.76%