Find out if your backtest is real before you trade it.

strategy('SMA Crossover')  .category('Strategy')  .tags('trend-following')  .input('fastLength', 'integer', { default: 8, min: 2, max: 200 })  .input('slowLength', 'integer', { default: 34, min: 5, max: 500 })  .input('source', 'source', { default: 'close' })  .state('prevFast', 'number')  .state('prevSlow', 'number')  .state('fastSMA', 'number')  .state('slowSMA', 'number')  .calculate(({ helpers, inputs, ta, state }) => {    const sourceData = helpers.lookback(inputs.slowLength, inputs.source);    const fastSMA = ta.sma(sourceData.slice(-inputs.fastLength), inputs.fastLength);    const slowSMA = ta.sma(sourceData, inputs.slowLength);    state.prevFast = state.fastSMA;    state.prevSlow = state.slowSMA;    state.fastSMA = fastSMA;    state.slowSMA = slowSMA;    return { fastSMA, slowSMA };  })  .entry(({ state }) => {    const crossUp = state.prevFast <= state.prevSlow && state.fastSMA > state.slowSMA;    const crossDown = state.prevFast >= state.prevSlow && state.fastSMA < state.slowSMA;    return { long: crossUp, short: crossDown };  })  .risk({ stopLoss: 2, maxPositions: 1, positionSize: 100 })  .build();