verdict

A lightweight decision tree/rules engine.

Features

- Support for complex branching logic
- Support for and/or boolean logic
- Wide range of operators supported
- Support for "fallback" values so paths don't "fall through the cracks" once an initial condition is met

Installation

Install with yarn:

``bash
yarn add verdict
`

Usage

`ts
import { DecisionTree, Operator } from 'verdict';

// Create a new DecisionTree
const tree = new DecisionTree({
condition: { path: 'quux', operator: Operator.Equals, value: 'bar' },
});

// Start by adding a child to the tree. Because the child doesn't specify a
// value, it's assumed to be a "branch" node which means that it's expected to
// have one or more children (at some point).
const child = tree.addChild({
condition: {
path: 'foo.bar',
operator: Operator.Equals,
value: 'baz',
},
});

// Follow the same process for adding another descendent (grandchild in this
// case). Note that it's not necessary to have this as a separate step. We
// easily could have included a children property within our first payload
// that we passed to addChild and included the grandchild there.
child.addChild({
condition: {
path: 'foo.baz',
operator: Operator.ContainsSubstring,
value: 'quux',
},
// Because the child has a value field, it's considered a leaf node.
value: Yay! I'm a leaf node!,
});

const data = {
quux: 'bar',
foo: {
bar: 'baz',
baz: 'oOoQuuXoOo',
},
};

console.log(tree.evaluate(data)); // Yay! I'm a leaf node!
`

If you're not interested in creating a decision tree, you can import Rule` from
the package and use it on its own.

$3

This library was inspired by verdict.js.