json-logic-engine v5.0.0-6
JSON Logic Engine
Fast, Powerful, and Persistable Logic
Have you ever needed the ability to write a custom set of logic or set of rules for a particular customer? Or needed to be able to configure a piece of logic on the fly?
JSON Logic might be your solution! Designed with a lisp-like syntax, JSON Logic makes it easy to write safe instructions that can be persisted into a database, and shared between the front-end and back-end.
Check out our Documentation Here.
The engine supports both synchronous & asynchronous operations, and can use function compilation to keep your logic performant at scale.
Examples:
The premise is the logic engine traverses the document you pass in, and each "object" is interpreted as an instruction for the engine to run.
logic.run({
'+': [1,2,3,4,5]
}) // 15
If you wanted to start factoring variables, you can pass a data object into it, and reference them using the "var" instruction:
logic.run({
'+': [11, { var: 'a' }]
}, {
'a': 17
}) // 28
The engine will also allow you to reference variables that are several layers deep:
logic.run({
'+': [{ var: 'a.b.c' }, 5]
}, {
a: { b: { c: 7 } }
}) // 12
Let's explore some slightly more complex logic:
logic.run({
'reduce': [{ var: 'x' }, { '+': [{ var: 'current' }, { var: 'accumulator' }] }, 0]
}, {
'x': [1,2,3,4,5]
}) // 15
In this example, we run the reduce operation on a variable called "x", and we set up instructions to add the "current" value to the "accumulator", which we have set to 0.
Similarly, you can also do map
operations:
logic.run({
'map': [[1,2,3,4,5], { '+': [{ var: '' }, 1] }]
}) // [2,3,4,5,6]
If var
is left as an empty string, it will assume you're referring to the whole variable that is accessible at the current layer it is looking at.
Example of a map accessing variables of the objects in the array:
logic.run({
'map': [{var : 'x'}, { '+': [{ var: 'a' }, 1] }]
},
{
'x': [{ a: 1 }, { a: 2 }, { a: 3 }, { a: 4 }]
}) // [2,3,4,5]
You can easily nest different operations in each other, like so:
logic.run({
max: [200, {
'*': [12, {var: 'a' }]
}]
}, {
a: 16
}) // 200
The engine also supports Handlebars-esque style traversal of data when you use the iterative control structures.
For example:
logic.run({
'map': [{var : 'x'}, { '+': [{ var: 'a' }, { var: '../../adder'}] }]
},
{
'x': [{ a: 1 }, { a: 2 }, { a: 3 }, { a: 4 }],
'adder': 7
}) // [8, 9, 10, 11]
This library was developed to be (for the most part) a drop-in replacement for the popular npm module json-logic-js
.
The intention of the library is to keep the functionality very similar to the original, while adding a few useful utilities.
9 months ago
9 months ago
9 months ago
8 months ago
11 months ago
11 months ago
11 months ago
9 months ago
9 months ago
9 months ago
10 months ago
10 months ago
10 months ago
10 months ago
8 months ago
8 months ago
8 months ago
10 months ago
10 months ago
10 months ago
10 months ago
10 months ago
10 months ago
11 months ago
11 months ago
10 months ago
10 months ago
11 months ago
12 months ago
12 months ago
12 months ago
1 year ago
1 year ago
1 year ago
1 year ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
2 years ago
3 years ago
3 years ago
3 years ago
3 years ago
3 years ago
3 years ago
3 years ago
3 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
4 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago
5 years ago