EMA

// The built-in EMA, as a script. The engine's ta.ema follows TradingView: it is seeded with the
// simple average of the first `length` values, so the first bars differ from the chart's old EMA.
indicator('EMA', { overlay: true });

const length = input.int('Length', 20, { min: 1 });
const source = input.source('Source', 'close');

const chart = bars();
const ema = ta.ema(length);
const line = plot.line('EMA');

chart.onBar(() => {
  line.set(ema.update(chart.source(source)));
});