README
jsonpath
Query JavaScript objects with JSONPath expressions. Robust / safe JSONPath engine for Node.js.
Query Example
var cities = [
{ name: "London", "population": 8615246 },
{ name: "Berlin", "population": 3517424 },
{ name: "Madrid", "population": 3165235 },
{ name: "Rome", "population": 2870528 }
];
var jp = require('jsonpath');
var names = jp.query(cities, '$..name');
// [ "London", "Berlin", "Madrid", "Rome" ]
Install
Install from npm:
$ npm install jsonpath
JSONPath Syntax
Here are syntax and examples adapted from Stefan Goessner's original post introducing JSONPath in 2007.
JSONPath | Description |
---|---|
$ |
The root object/element |
@ |
The current object/element |
. |
Child member operator |
.. |
Recursive descendant operator; JSONPath borrows this syntax from E4X |
* |
Wildcard matching all objects/elements regardless their names |
[] |
Subscript operator |
[,] |
Union operator for alternate names or array indices as a set |
[start:end:step] |
Array slice operator borrowed from ES4 / Python |
?() |
Applies a filter (script) expression via static evaluation |
() |
Script expression via static evaluation |
Given this sample data set, see example expressions below:
{
"store": {
"book": [
{
"category": "reference",
"author": "Nigel Rees",
"title": "Sayings of the Century",
"price": 8.95
}, {
"category": "fiction",
"author": "Evelyn Waugh",
"title": "Sword of Honour",
"price": 12.99
}, {
"category": "fiction",
"author": "Herman Melville",
"title": "Moby Dick",
"isbn": "0-553-21311-3",
"price": 8.99
}, {
"category": "fiction",
"author": "J. R. R. Tolkien",
"title": "The Lord of the Rings",
"isbn": "0-395-19395-8",
"price": 22.99
}
],
"bicycle": {
"color": "red",
"price": 19.95
}
}
}
Example JSONPath expressions:
JSONPath | Description |
---|---|
$.store.book[*].author |
The authors of all books in the store |
$..author |
All authors |
$.store.* |
All things in store, which are some books and a red bicycle |
$.store..price |
The price of everything in the store |
$..book[2] |
The third book |
$..book[(@.length-1)] |
The last book via script subscript |
$..book[-1:] |
The last book via slice |
$..book[0,1] |
The first two books via subscript union |
$..book[:2] |
The first two books via subscript array slice |
$..book[?(@.isbn)] |
Filter all books with isbn number |
$..book[?(@.price<10)] |
Filter all books cheaper than 10 |
$..book[?(@.price==8.95)] |
Filter all books that cost 8.95 |
$..book[?(@.price<30 && @.category=="fiction")] |
Filter all fiction books cheaper than 30 |
$..* |
All members of JSON structure |
Methods
jp.query(obj, pathExpression[, count])
Find elements in obj
matching pathExpression
. Returns an array of elements that satisfy the provided JSONPath expression, or an empty array if none were matched. Returns only first count
elements if specified.
var authors = jp.query(data, '$..author');
// [ 'Nigel Rees', 'Evelyn Waugh', 'Herman Melville', 'J. R. R. Tolkien' ]
jp.paths(obj, pathExpression[, count])
Find paths to elements in obj
matching pathExpression
. Returns an array of element paths that satisfy the provided JSONPath expression. Each path is itself an array of keys representing the location within obj
of the matching element. Returns only first count
paths if specified.
var paths = jp.paths(data, '$..author');
// [
// ['