Get Started with a JSONPath Evaluation

Installation

npm install @jsonpath-tools/jsonpath

Selecting JSON Values

import { JSONPath } from "@jsonpath-tools/jsonpath";

const queryArgument = {
    books: [
        { title: "1984", author: "George Orwell" },
        { title: "Epic of Gilgamesh", author: null },
        { title: "The Old Man and the Sea", author: "Ernest Hemingway" }
    ]
};

const nodes = JSONPath.select(`$.books[?@.author != null].title`, queryArgument);

Getting the selected values:

const values = nodes.toValues();

Getting paths to the selected values:

const paths = nodes.toNormalizedPaths();

Transforming JSON Values

Replacing values:

const replaced = JSONPath.replace(`$.books[?@.author != null].title`, queryArgument, "New title");

With a function:

const replaced = JSONPath.replace(`$.books[?@.author != null].title`, queryArgument, v => (v as string).toUpperCase());

Removing values:

const removed = JSONPath.remove(`$.books[?@.author != null].title`, queryArgument);

Parsing a Query

const query = JSONPath.parse(`$.books[?@.title == "1984", 3141]`);

The result syntax tree will look like this: