# jokenizer

> Tokenize javascript expressions.

Latest version **1.0.1** (published 2026-07-18) · MIT license · 0 weekly downloads

## Install

```sh
npm install jokenizer
pnpm add jokenizer
yarn add jokenizer
bun add jokenizer
```

## Health

**Score 65/100 (B)** — status: active.

Positive: has types; no vulnerabilities; has provenance; recently updated; high quality score.

Warnings: low downloads; no esm support.

## Facts

| | |
|---|---|
| Version | 1.0.1 |
| Published | 2026-07-18 |
| First published | 2018-08-21 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Dependencies | 0 |
| Unpacked size | 70 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| Author | Umut Özel |
| Maintainers | umutozel |
| Keywords | expression, parser, tokenizer, evaluator, typescript |

## Links

- npm: https://www.npmjs.com/package/jokenizer
- Repository: https://github.com/umutozel/jokenizer
- Homepage: https://github.com/umutozel/jokenizer#readme
- Issues: https://github.com/umutozel/jokenizer/issues
- npm.io page: https://npm.io/package/jokenizer

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## Recent versions

- 1.0.1 (latest) — 2026-07-18
- 1.0.0 — 2025-02-12
- 0.4.5 — 2020-08-06
- 0.4.4 — 2020-08-06
- 0.4.3 — 2020-02-10
- 0.4.2 — 2019-08-20
- 0.4.1 — 2019-08-16
- 0.4.0 — 2019-06-10
- 0.3.0 — 2019-03-23
- 0.2.9 — 2019-02-18
- 0.2.8 — 2019-01-30
- 0.2.7 — 2019-01-28
- 0.2.6 — 2018-10-24
- 0.2.5 — 2018-10-04
- 0.2.4 — 2018-09-26
- … 9 more at https://npm.io/package/jokenizer/versions

## README

# Jokenizer - JavaScript Expression Parser and Evaluator

[![Build and Test](https://github.com/umutozel/jokenizer/actions/workflows/build.yml/badge.svg)](https://github.com/umutozel/jokenizer/actions/workflows/build.yml)
[![codecov](https://codecov.io/gh/umutozel/jokenizer/graph/badge.svg?token=MXSq1ImgQJ)](https://codecov.io/gh/umutozel/jokenizer)
<a href="https://snyk.io/test/npm/jokenizer"><img src="https://snyk.io/test/npm/jokenizer/badge.svg" alt="Known Vulnerabilities" data-canonical-src="https://snyk.io/test/npm/jokenizer" style="max-width:100%;"></a>

[![npm version](https://img.shields.io/npm/v/jokenizer)](https://www.npmjs.com/package/jokenizer)
[![npm downloads](https://img.shields.io/npm/dm/jokenizer.svg)](https://www.npmjs.com/package/jokenizer)

[![GitHub issues](https://img.shields.io/github/issues/umutozel/Jokenizer.Net.svg)](https://github.com/umutozel/Jokenizer.Net/issues)
[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/umutozel/Jokenizer.Net/main/LICENSE)
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jokenizer is just a simple library to parse JavaScript expressions and evaluate them with custom scopes.

Written completely in TypeScript.

## Installation

```shell
npm i jokenizer
```

## Let's try it out

```JavaScript
import { tokenize, evaluate } from 'jokenizer';

const expression = tokenize('{ a: v1, b }');
const scope = { v1: 3, b: 5 };
const value = evaluate(expression, scope);

/*
expression =
{
    "type": "O",          // ObjectExpression
    "members": [{
        "type": "A",      // AssignExpression
        "name": "a",
        "right": {
            "type": "V",  // VariableExpression
            "name": "v1"
        }
    }, {
        "type": "V",
        "name": "b"
    }]
}

value = { "a": 3, "b": 5 }     // evaluated value
*/
```

## Supported Expression Types

### LiteralExpression

```JavaScript
evaluate(tokenize('42'));               //  42
evaluate(tokenize('42.4242'));          //  42.4242
evaluate(tokenize('"4\'2"'));           //  "4'2"
evaluate(tokenize('true'));             //  true
evaluate(tokenize('false'));            //  false
evaluate(tokenize('null'));             //  null
```

### VariableExpression

```JavaScript
evaluate(tokenize('Name'), { Name: 'Alan' });       //  'Alan'
```

### UnaryExpression

```JavaScript
evaluate(tokenize('-Str'), { Str: '5' });               //  -5
evaluate(tokenize('+Str'), { Str: '5' });               //  5
evaluate(tokenize('!IsActive'), { IsActive: false });   //  true
evaluate(tokenize('~index'), { index: -1 });            //  0
```

### GroupExpression

```JavaScript
evaluate(tokenize('(a, b)'), { a: 4, b: 2 });   //  [1, 2]
evaluate(tokenize('a, b'), { a: 4, b: 2 });     //  [4, 2]
evaluate(tokenize('(a)'), { a: 4 });            //  4   - if expression count is 1, returns its value
```

### ObjectExpression

```JavaScript
evaluate(tokenize('{ a: v1, b }'), { v1: 3, b: 5 });    //  { a: 3, b: 5 }
```

### ArrayExpression

```JavaScript
evaluate(tokenize('[ a, 1 ]'), { a: 0 });               //  [0, 1]
```

### BinaryExpression

```JavaScript
evaluate(tokenize('v1 <= v2'), { v1: 5, v2: 3 });           //  false
evaluate(tokenize('v1 % v2'), { v1: 5, v2: 3 });            //  2
evaluate(tokenize('v1 * v2'), { v1: 5, v2: 3 });            //  15
evaluate(tokenize('v1 && v2'), { v1: true, v2: false });    //  false
evaluate(tokenize('1 + 2 * 3'));                            //  7   - supports operator precedence
```

### MemberExpression

```JavaScript
evaluate(tokenize('Company.Name'), { Company: { Name: 'Netflix' } });       //  'Netflix'
```

### IndexerExpression

```JavaScript
evaluate(tokenize('Company["Name"]'), { Company: { Name: 'Netflix' } });                //  'Netflix'
evaluate(tokenize('Company[key]'), { Company: { Name: 'Netflix' }, key: 'Name' });      //  'Netflix'
```

### FuncExpression

```JavaScript

const f = evaluate(tokenize('(a, b) => a < b'));
f(2, 1);        //  false

const f = evaluate(tokenize('function(a, b) { return a < b; }'));
f(2, 1)         //  false
```

### CallExpression

```JavaScript
evaluate(tokenize('test(42, a)'), { test: (a, b) => a * b }, { a: 2 });     //  84
```

### TernaryExpression

```JavaScript
evaluate(tokenize('check ? 42 : 21'), { check: true });     //  42
```

## License

Jokenizer is under the [MIT License](LICENSE).

---
_Source: https://npm.io/package/jokenizer · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._