Jora

JavaScript object query language, and a library to process and perform Jora queries on data.

STATUS: Jora is stable, but syntax may change in next releases. Still very much work in progress (ideas and thoughts).

Features:

• Tolerant to data stucture queries (e.g. just returns nothing for paths that not reachable)
• Compact syntax for common tasks
• Aggregate values across arrays and eliminate duplicates by default
• Stat collecting mode (powers suggestions)
• Tolerant parsing mode (useful to provide suggestions for query in an editor)
• Extensible DSL on query build by custom method list

Related projects:

• Discovery – Uses jora as core fuctionality to transform a data flow for views and query data for reports
• JsonDiscovery – a browser’s extension based on Discovery for viewing JSON documents, available for Chrome and Firefox (read more Changing a way we’re viewing JSON in a browser)
• jora-cli – Command line interface for transforming data using Jora
• Jora sandbox – A Web interface where you can play with jora syntax or transform some JSON with zero setup

Table of content:

• Query syntax overview
  • Comments
  • Expressions
  • Literals
  • Operators
  • Dot, bracket and slice notations
  • Methods and functions
  • Mapping and filtering
  • Variables
• NPM package
  • Install & import
  • API
  • Quick demo

Query syntax overview

Jora is a query language designed for JSON-like data structures. It extends JSON5 and shares many similarities with JavaScript.

See Docs & playground.

Comments

// single-line comment/* multi-linecomment */

Expressions

Jora expressions are the building blocks of Jora queries. Expressions can include comments, literals, operators, functions, and variables.

Literals

Jora supports literals, which include:

• Numbers: 42, -3.14, 6.022e23
• Strings: "hello", 'world', `template${yes}`, "\u{1F600}"
• Booleans: true, false
• Regular expressions: /regexp/flags
• Object literals: { hello: 'world' } (see Object literals)
• Array literals: [1, 2, 3] (see Array literals)
• Functions: => … (see Functions)
• Keywords: NaN, Infinity, null and undefined

See Literals

Operators

Jora supports most JavaScript operators, including:

• Arithmetic: +, -, *, /, %
• Comparison: =, !=, <, <=, >, >=, ~=
• Logical: and, or, not (alias no), ??, is, in, not in, has, has no
• Ternary: ?:
• Grouing: ( )
• Pipeline: |

See Operators

Dot, bracket and slice notations

Jora provides notations for accessing properties and elements: dot, bracket and slice notations. Dot notation is similar to JavaScript's property access notation, using a period followed by the property name (e.g., $.propertyName). Bracket notation encloses the property name or index within square brackets (e.g., $['propertyName'] or $[0]), it's also possible to use functions to choose. Slice notation provides a concise syntax to slice elements with optional step (array[5:10:2] selects each odd element from 5th to 10th indecies).

• Dot notation
• Bracket notation
• Slice notation

Methods and functions

Jora provides a rich set of built-in methods for manipulating data, such as map(), filter(), group(), sort(), reduce(), and many others. You can also define custom functions using the => arrow function syntax, and use them as a method.

• Functions
• Methods
• Built-in methods
• Grouping: group() method
• Sorting: sort() method

Mapping and filtering

Jora has a concise syntax for mapping and filtering. The map(fn) method is equivalent to .(fn()), while the filter(fn) method is equivalent to .[fn()].

• Filtering: .[…] and filter() method
• Mapping: .(…) and map() method
• Recursive mapping: ..(…)

Variables

Variables in Jora are helpful for storing intermediate results or simplifying complex expressions. To define a variable, use the $variableName: expression; syntax.

See Variables

NPM package

Install & import

Install with npm:

npm install jora

Basic usage:

// ESMimportjorafrom'jora';// CommonJSconstjora=require('jora');

Bundles are available for use in a browser:

• dist/jora.js – minified IIFE with jora as global

<scriptsrc="node_modules/jora/dist/jora.js"></script><script>jora('query')(data,context);</script>

• dist/jora.esm.js – minified ES module

<scripttype="module">importjorafrom'node_modules/jora/dist/jora.esm.js'// ...</script>

By default (for short path) a ESM version is exposing. For IIFE version a full path to a bundle should be specified. One of CDN services like unpkg or jsDelivr can be used:

• jsDeliver

  <!-- ESM --><scripttype="module">importjorafrom'https://cdn.jsdelivr.net/npm/jora';</script>

  <!-- IIFE with an export `jora` to global --><scriptsrc="https://cdn.jsdelivr.net/npm/jora/dist/jora.js"></script>

• unpkg

  <!-- ESM --><scripttype="module">importjorafrom'https://unpkg.com/jora';</script>

  <!-- IIFE with an export `jora` to global --><scriptsrc="https://unpkg.com/jora/dist/jora.js"></script>

API

importjorafrom'jora';// create a queryconstquery=jora('foo.bar');// perform a queryconstresult=query(data,context);

See the details in Jora library API

Quick demo

Get npm dependency paths (as a tree) that have packages with more than one version:

importjorafrom'jora';import{exec}from'child_process';functionprintTree(){// see implementation in examples/npm-ls.js}exec('npm ls --all --json',(error,stdout)=>{if(error){return;}constnpmTree=JSON.parse(stdout);constdepsPathsToMultipleVersionPackages=jora(` $normalizedDeps: => dependencies.entries().({ name: key, ...value }); $multiVersionPackages: ..$normalizedDeps() .group(=>name, =>version) .({ name: key, versions: value.sort() }) .[versions.size() > 1]; $pathToMultiVersionPackages: => .($name; { name, version, otherVersions: $multiVersionPackages[=>name=$name].versions - version, dependencies: $normalizedDeps() .$pathToMultiVersionPackages() .[name in $multiVersionPackages.name or dependencies] }); $pathToMultiVersionPackages() `)(npmTree);printTree(depsPathsToMultipleVersionPackages);});

Example of output:

jora@1.0.0
├─ c8@7.11.0
│ ├─ istanbul-lib-report@3.0.0
│ │ └─ supports-color@7.2.0 [more versions: 8.1.1]
│ ├─ test-exclude@6.0.0
│ │ └─ minimatch@3.1.2 [more versions: 3.0.4]
│ ├─ v8-to-istanbul@8.1.1
│ │ └─ convert-source-map@1.8.0
│ │ └─ safe-buffer@5.1.2 [more versions: 5.2.1]
│ ├─ yargs-parser@20.2.9 [more versions: 20.2.4]
│ └─ yargs@16.2.0
│ └─ yargs-parser@20.2.9 [more versions: 20.2.4]
├─ eslint@8.10.0
│ ├─ @eslint/eslintrc@1.2.0
│ │ ├─ ignore@4.0.6 [more versions: 5.2.0]
│ │ └─ minimatch@3.1.2 [more versions: 3.0.4]
...

See more examples in Complex Jora query examples