condition.js is a lightweight JavaScript library that enables you to use a comprehensible string syntax to run complex filter operations on a set of JSONs (or only one for that matter). The syntax is strongly inspired by the syntax for the expression of conditions in SQL and is meant to be simple and intuitive, even for non-technical people. See a demo!

Install

npm i @mg98/condition-js

Example

import { matchCondition } from 'condition-js';

const clients = [
    {
        name: 'Batu',
        age: 17,
        country: 'Turkey'
    },
    {
        name: 'Hai Dang',
        age: 24,
        country: 'Vietnam'
    },
    {
        name: 'Miles',
        age: 16,
        country: 'USA'
    },
    {
        name: 'Philipp',
        age: 58,
        country: 'Germany'
    }
]

const alcoholClients = data.filter(client => matchCondition(client, 
  "(age >= 18 and country in ('Germany', 'Turkey', 'Vietnam') or age >= 21 and country = 'USA') and country != 'Arabia'"
));

console.log(alcoholClients);
// [
//     {
//         name: 'Hai Dang',
//         age: 24,
//         country: 'Vietnam'
//     },
//     {
//         name: 'Philipp',
//         age: 58,
//         country: 'Germany'
//     }
// ]

Features

The goal of condition.js is to create a language that is not only a powerful tool, but also a convenient and fault-tolerant one.

✅ Basic comparison operators =, !=, >, <, >=, <=

✅ Operators in and not in in combination with array values (('Apple', 'Peach', 'Banana'))

✅ Supports value types string and number (including floating values)

✅ Supports operations on arrays (e.g. hobbies > 3 is valid if hobbies in an array of length > 3)

✅ Logical operators and and or to combine expressions

✅ Deep property access (e.g. address.street = 'Elm Str')

✅ Nested expressions using parantheses

Not yet supported...

❌ Boolean type