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:
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.
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'
, "\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
), ??
, 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:
import jora from 'jora';
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
<script type="module">
import jora from 'https://cdn.jsdelivr.net/npm/jora';
</script>
<script src="https://cdn.jsdelivr.net/npm/jora/dist/jora.js"></script>
-
unpkg
<script type="module">
import jora from 'https://unpkg.com/jora';
</script>
<script src="https://unpkg.com/jora/dist/jora.js"></script>
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() {
}
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]
...
API
import jora from 'jora';
const query = jora('foo.bar');
const queryWithCustomMethods = jora.setup({
myMethod(current) { }
});
const result = query(data, context);
const result = queryWithCustomMethods('foo.myMethod()')(data, context);
Options:
-
methods
Type: Object
Default: undefined
Additional methods for using in query passed as an object, where a key is a method name and a value is a function to perform an action. It can override build-in methods.
-
debug
Type: Boolean
or function(name, value)
Default: false
Enables debug output. When set a function, this function will recieve a section name and its value.
-
tolerant
Type: Boolean
Default: false
Enables tolerant parsing mode. This mode supresses parsing errors when possible.
-
stat
Type: Boolean
Default: false
Enables stat mode. When mode is enabled a query stat interface is returning instead of resulting data.
Query introspection
To introspect a query, it should be compiled in "stat" (statistic) mode by passing a stat
option. In this case a result of the query evaluation will be a special API with encapsulated state instead of a value:
import jora from 'jora';
const query = jora('...query...', { stat: true });
const statApi = query(data);
The returned API allows fetching the values which are passed through a location in a query (the stat()
method) as well as a list of suggestions for a location (the suggestion()
method):
import jora from 'jora';
const query = jora('.[foo=""]', { stat: true });
const statApi = query([{ id: 1, foo: "hello" }, { id: 2, foo: "world" }]);
statApi.stat(3);
statApi.suggestion(3);
statApi.suggestion(7);
That's an effective way to use stat mode together with tolerant
mode for incomplete queries:
import jora from 'jora';
const query = jora('.[foo=]', {
stat: true,
tolerant: true
});
const statApi = query([{ id: 1, foo: "hello" }, { id: 2, foo: "world" }]);
statApi.suggestion(6);
Methods
-
stat(pos: number, includeEmpty?: boolean)
Returns an array of ranges with all the values which are passed through pos
during performing a query.
Output format:
suggestion(): Array<{
context: 'path' | 'key' | 'value' | 'in-value' | 'value-subset' | 'var',
from: number,
to: number,
text: string,
values: Set<any>,
related: Set<any> | null
}> | null
-
suggestion(pos: number, options?)
Returns suggesion values grouped by a type or null
if there is no any suggestions. The following options are supported (all are optional):
limit
(default: Infinity
) – a max number of the values that should be returned for each value type ("property"
, "value"
or "variable"
)sort
(default: false
) – a comparator function (should take 2 arguments and return a negative number, 0
or a positive number) for value list sorting, makes sence when limit
is usedfilter
(default: function
) – a filter function factory (pattern => value => <expr>
) to discard values from the result when returns a falsy value (default is equivalent to patttern => value => String(value).toLowerCase().includes(pattern)
)
Output format:
suggestion(): Array<{
type: 'property' | 'value' | 'variable',
from: number,
to: number,
text: string,
suggestions: Array<string | number>
}> | null