Blazing Fast via Compilation

json-logic-engine has support for logic compilation which greatly enhances run-time performance of your logic. In a number of (simpler) cases, it can get rather close to native performance. Additionally, as of v2.0.0, the interpreter has an optimizer that can cache the execution plan of the logic if re-used, improving interpreted performance without the need for compilation.

Running many iterations of json-logic-js's test suite, we can observe stark performance differences between the built versions of the json-logic-engine against json-logic-js.

> node test.js
json-logic-js: 5.617s
le interpreted: 5.287s
le interpreted (optimized): 2.725s
le built: 756.049ms
le async interpreted: 4.725s
le async built: 2.231s

This comparison is not fair though, as the compilation mechanism is able to evaluate whether a particular branch is deterministic & pre-compute portions of the logic in advance. Running a different test suite that can't be pre-computed yields:

> node test.js
json-logic-js: 312.856ms
le interpreted: 287.769ms
le interpreted (optimized): 79.886ms
le built: 15.186ms
le async interpreted: 130.97ms
le async built: 53.791ms

Additionally, the compilation mechanism allows the asynchronous version of the engine to perform quite well against its interpreted counter-part.

> node perf.js & node perf2.js
interpreted: 8.765s
interpreted (optimized): 796.726ms
built: 130.512ms

---

Comparing the engine against an alternative library like json-rules-engine,

{
  any: [{
    all: [{
      fact: 'gameDuration',
      operator: 'equal',
      value: 40
    }, {
      fact: 'personalFoulCount',
      operator: 'greaterThanInclusive',
      value: 5
    }]
  }, {
    all: [{
      fact: 'gameDuration',
      operator: 'equal',
      value: 48
    }, {
      fact: 'personalFoulCount',
      operator: 'greaterThanInclusive',
      value: 6
    }]
  }]
}

vs

{
  or: [
    {
      and: [{
        '===': [40, { var: 'gameDuration' }]
      }, {
        '>=': [{ var: 'personalFoulCount' }, 5]
      }]
    },
    {
      and: [{
        '===': [48, { var: 'gameDuration' }]
      }, {
        '>=': [{ var: 'personalFoulCount' }, 6]
      }]
    }
  ]
}

The performance difference is significant:

> node rules.js
json-logic-engine: 54.421ms
json-rules-engine: 9.153s

---

To use this feature, you merely have to call:

const func = engine.build(logic)

And invoke func with the data you'd like to run it with.