proptest / fast-check

const f = (a,b) => a+b; // proptest const QC = require('proptest'); const property = QC.createProperty((label, r) => { r(); }) try { property( 'is commutative', QC.nat.array(), x => x.indexOf(8) === -1); } catch(err) { console.log(err); } // fast-check const fc = require('fast-check'); try { fc.assert( fc.property( fc.array(fc.nat()), x => x.indexOf(8) === -1)); } catch(err) { console.log(err); }