JSONPath in JavaScript: Querying JSON
Using jsonpath-plus and JSONPath in JavaScript for data transformation and filter expressions.
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Tags: JSONPath JavaScript library, jsonpath-plus npm, JavaScript JSON query
JSONPath in JavaScript: Querying JSON The JSONPath specification (IETF RFC 9535) defines the query language. The jsonpath-plus npm package provides a widely-used JavaScript implementation with extended features. For the original informal spec, see Stefan Goessner's JSONPath article. Writing to extract active emails is boilerplate. does the same in one call — and generalizes to any structure without code changes. --- What is installing jsonpath-plus? TypeScript types are included — no package needed. For browser use without a bundler, a UMD build is available: --- What is basic usage? JSONPath always returns an array. For a single expected value: --- What is filter expressions? --- What is resulttype options? The path output uses as separator by default. Use when you need to know where…
Frequently Asked Questions
How do I use JSONPath in JavaScript?
Install jsonpath-plus with npm install jsonpath-plus. Import JSONPath and call it with a path expression and your JSON data: JSONPath({ path: '$.users[*].email', json: data }). It returns an array of matching values, or an empty array if nothing matched.
What is jsonpath-plus?
jsonpath-plus is the most complete JSONPath implementation for JavaScript and Node.js. It implements the original Goessner spec plus extensions like type filters, parent access, and substitution. It works in both Node.js and modern browsers and has TypeScript type definitions included.
How do I filter arrays with JSONPath?
Use a filter expression inside square brackets: $.users[?(@.active == true)].name or $.items[?(@.price < 10)]. The @ symbol refers to the current array element. You can combine conditions with && and || operators.
How do I use JSONPath with fetch responses?
After await res.json(), pass the parsed object directly to JSONPath: const result = JSONPath({ path: '$.data.users[*].id', json: await res.json() }). No additional parsing needed — JSONPath works on plain JavaScript objects.
What is the difference between JSONPath and jq?
JSONPath is a JavaScript-friendly library that works in browsers and Node.js. jq is a standalone CLI tool with a richer expression language, better suited for shell scripting and terminal data transformation. JSONPath is for JavaScript code; jq is for shell commands.
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