https://github.com/joonhocho/expjson

Super lightweight, fast, and optimized evaluate-able and compilable expressions in JSON written in TypeScript
https://github.com/joonhocho/expjson

Last synced: about 1 month ago
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Super lightweight, fast, and optimized evaluate-able and compilable expressions in JSON written in TypeScript

• Host: GitHub
• URL: https://github.com/joonhocho/expjson
• Owner: joonhocho
• License: mit
• Created: 2019-08-01T10:27:46.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2023-01-04T05:59:44.000Z (almost 2 years ago)
• Last Synced: 2024-11-01T04:35:29.680Z (about 2 months ago)
• Language: TypeScript
• Homepage:
• Size: 812 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 12
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# expjson

Super lightweight, fast, and optimized evaluate-able and compilable expressions in JSON written in TypeScript

[![npm version](https://badge.fury.io/js/expjson.svg)](https://badge.fury.io/js/expjson)

[![npm](https://img.shields.io/npm/dw/expjson.svg)](https://www.npmjs.com/package/expjson)

![npm type definitions](https://img.shields.io/npm/types/expjson.svg)

[![Build Status](https://travis-ci.org/joonhocho/expjson.svg?branch=master)](https://travis-ci.org/joonhocho/expjson)

[![Dependency Status](https://david-dm.org/joonhocho/expjson.svg)](https://david-dm.org/joonhocho/expjson)

[![GitHub](https://img.shields.io/github/license/joonhocho/expjson.svg)](https://github.com/joonhocho/expjson/blob/master/LICENSE)

## Get Started

```

npm install -D expjson

```

or

```

yarn add -D expjson

```

## How to Use

`compileExpression` and running it later is much faster if compiled expression is evaluated multiple times on many execution contexts.

`evaluateExpression` is faster if the expression is evaluated only once.

functionalities are exactly same for both.

```typescript

import {

  compileExpression,

  evaluateExpression,

  // operators

  Add,

  And,

  Divide,

  Equal,

  GreaterThan,

  GreaterThanOrEqual,

  IfThenElse,

  In,

  LessThan,

  LessThanOrEqual,

  Modulo,

  Multiply,

  Not,

  NotEqual,

  NotIn,

  Or,

  Subtract,

  Var,

} from 'expjson';

// evaluateExpression: evaluate without compile

expect(

  evaluateExpression(

    [

      IfThenElse, // same as '?:'

      [In, 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

      [Not, [Var, 'postDeleted']], // true if context variable "postDeleted" is false

      [Var, 'unauthorized'], // context variable "unauthorized"

    ],

    {

      postDeleted: false,

      roles: ['user', 'admin'],

      unauthorized: 'Unauthorized Error',

    }

  )

).toBe(true);

expect(

  evaluateExpression(

    [

      '?:', // same as IfThenElse

      ['In', 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

      ['!', [Var, 'postDeleted']], // true if context variable "postDeleted" is false

      [Var, 'unauthorized'], // context variable "unauthorized"

    ],

    {

      postDeleted: true,

      roles: ['user', 'admin'],

      unauthorized: 'Unauthorized Error',

    }

  )

).toBe(false);

expect(

  evaluateExpression(

    [

      IfThenElse, // same as '?:'

      [In, 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

      [Not, [Var, 'postDeleted']], // true if context variable "postDeleted" is false

      [Var, 'unauthorized'], // context variable "unauthorized"

    ],

    {

      postDeleted: false,

      roles: ['user', 'guest'],

      unauthorized: 'Unauthorized Error',

    }

  )

).toBe('Unauthorized Error');

// compileExpression: compile then evaluate

const compiled1 = compileExpression([

  IfThenElse, // same as '?:'

  [In, 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

  [Not, [Var, 'postDeleted']], // true if context variable "postDeleted" is false

  [Var, 'unauthorized'], // context variable "unauthorized"

]);

expect(

  compiled1({

    postDeleted: false,

    roles: ['user', 'admin'],

    unauthorized: 'Unauthorized Error',

  })

).toBe(true);

const compiled2 = compileExpression([

  '?:', // same as IfThenElse

  ['In', 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

  ['!', [Var, 'postDeleted']], // true if context variable "postDeleted" is false

  [Var, 'unauthorized'], // context variable "unauthorized"

]);

expect(

  compiled2({

    postDeleted: true,

    roles: ['user', 'admin'],

    unauthorized: 'Unauthorized Error',

  })

).toBe(false);

const compiled3 = compileExpression([

  IfThenElse, // same as '?:'

  [In, 'admin', [Var, 'roles']], // test if "admin" is in "roles" context variable

  [Not, [Var, 'postDeleted']], // true if context variable "postDeleted" is false

  [Var, 'unauthorized'], // context variable "unauthorized"

]);

expect(

  compiled3({

    postDeleted: false,

    roles: ['user', 'guest'],

    unauthorized: 'Unauthorized Error',

  })

).toBe('Unauthorized Error');

```

## License

[MIT License](https://github.com/joonhocho/expjson/blob/master/LICENSE)