RunKit + npm: @createvibe/replayproxy

const replayproxy = require('@createvibe/replayproxy'); function performPotentialDangerousTask(chunks) { // create a random chunk of numbers const chunk = []; const len = Math.ceil(Math.random() * 10); for (let i = 0; i < len; i++) { chunk.push(Number(Math.random() * 10).toFixed(3)); } // brute force merge of 10 random numbers in sorted order chunk.sort((a,b) => (a-b)); chunks.push(chunk); // chunks.sort((a,b) => (a-b)); // randomly throw an error if (Math.random() * 4 > 3.5 && chunks.length > 3) { throw new Error('I make Error!'); } } const data = {}; /* do something with data */ data.something = 'some value'; data.array = [6,4,1,4,2,15,26,25,18,11,14,35,25,74,21,7,6,3]; data.array.sort((a,b) => (a-b)); data.array = [data.array]; { // wrap data with replayproxy let proxy = replayproxy(data); // create a breakpoint reference let breakpoint; // do dangerous things with data (the proxy) try { // do stuff continuously until we get an error for (;;) { // pass proxy instead of data performPotentialDangerousTask(proxy.array); // create a new breakpoint breakpoint = proxy.breakpoint(); } } catch (err) { console.error(err); // found an error, rollback the changes to the last breakpoint console.log('data count before rollbak ' + data.array.length); console.log('the data being rolled back', data.array[ data.array.length - 1 ]); // perform rollback to last known breakpoint proxy.rollback(breakpoint); console.log('data count after rollback ' + data.array.length); console.log('the last element of the array has changed', data.array[ data.array.length - 1 ]); } // dismiss proxy so GC can do its thing proxy = null; } /* continue working with data instead of proxy */ console.log(data);