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Jora

NPM version Build Status Coverage Status Twitter

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:

Table of content:

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-line
comment */

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).

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.

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()].

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:

// ESM
import jora from 'jora';

// CommonJS
const jora = require('jora');

Bundles are available for use in a browser:

  • dist/jora.js – minified IIFE with jora as global
<script src="node_modules/jora/dist/jora.js"></script>
<script>
  jora('query')(data, context);
</script>
  • dist/jora.esm.js – minified ES module
<script type="module">
  import jora from '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 -->
<script type="module">
import jora from 'https://cdn.jsdelivr.net/npm/jora';
</script>
    <!-- IIFE with an export `jora` to global -->
<script src="https://cdn.jsdelivr.net/npm/jora/dist/jora.js"></script>

  • unpkg

    <!-- ESM -->
<script type="module">
import jora from 'https://unpkg.com/jora';
</script>
    <!-- IIFE with an export `jora` to global -->
<script src="https://unpkg.com/jora/dist/jora.js"></script>

API

import jora from 'jora';

// create a query
const query = jora('foo.bar');

// perform a query
const result = 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:

import jora from 'jora';
import { exec } from 'child_process';

function printTree() {
    // see implementation in examples/npm-ls.js
}

exec('npm ls --all --json', (error, stdout) => {
    if (error) {
        return;
    }

    const npmTree = JSON.parse(stdout);
    const depsPathsToMultipleVersionPackages = 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