function generateDOMData(start, end, step, amount) {

  const answer = [];

  const steps = Math.abs((end - start) / step);

​

  let count = 0;

  for (let i = start; step < 0 ? i >= end : i <= end; i += step) {

    count += 1;

    answer.push({

      price: i,

      volume: (0.8 + 0.1 * Math.random()) * amount * ((steps - count) / steps)

    });

  }

  return answer;

}

​

function initOnReady() {

  class TestDatafeed extends Datafeeds.UDFCompatibleDatafeed {

    constructor(datafeedURL, updateFrequency, limitedServerResponse) {

      super(datafeedURL, updateFrequency, limitedServerResponse);

      this._depthSubscriptions = {};

    }

​

    subscribeDepth(symbol, callback) {

      const subscriptionUniqueId = this._createDepthSubscription(

        'https://myserver.com',

        symbol,

        callback

      );

      return subscriptionUniqueId;

    }

​

    unsubscribeDepth(listenerID) {

      this._removeDepthSubscription(listenerID);

    }

​

    _createDepthSubscription(server, symbol, callback) {

      // Create an uniqueID

      const uniqueId = Math.round(Math.random() * 10000000).toString(36);

      const latestPrice = 173;

​

      // Mocked data, using setInterval to fake data updates

      const intervalId = setInterval(() => {

        const data = {

          snapshot: true,

          bids: generateDOMData(

            latestPrice + 0.05,

            latestPrice + 10,

            0.01,

            10000

          ),

          asks: generateDOMData(

            latestPrice - 0.05,

            latestPrice - 10,

            -0.01,

            10000

          )

        };

        callback(data);

      }, 1000);

      this._depthSubscriptions[uniqueId] = intervalId;

      return uniqueId;

    }

​

    _removeDepthSubscription(listenerID) {

      const intervalId = this._depthSubscriptions[listenerID];

      clearInterval(intervalId);

    }

  }

​

  class CustomBroker extends Brokers.BrokerSample {

      isTradable() {

        /* If this property returns false, then when trying to view the DOM widget

           nothing will be displayed, and after a minute (or a quite a few seconds)

           console errors will start to appear.

        */

        return Promise.resolve(true);

      }

  }

​

  var datafeed = new TestDatafeed("https://demo-feed-data.tradingview.com");

  var widget = (window.tvWidget = new TradingView.widget({

    library_path:

      "https://trading-terminal.tradingview-widget.com/charting_library/",

    // debug: true, // uncomment this line to see Library errors and warnings in the console

    fullscreen: true,

    symbol: "AAPL",

    interval: "1D",

    container: "tv_chart_container",

    datafeed: datafeed,

    locale: "en",

    disabled_features: ["order_panel"],

    enabled_features: [

      "dom_widget",

      "hide_right_toolbar",

      "hide_right_toolbar_tabs"

    ],

    custom_formatters: {

      studyFormatterFactory: (format, symbolInfo) => {

        if (format.type === "volume") {

          return {

            format: (value) => value.toPrecision(8)

          };

        }

        return null;

      }

    },

    settings_adapter: {

      initialSettings: {

        "trading.chart.proterty": '{"showSellBuyButtons":0}'

      },

      setValue: function (key, value) {

        console.log(key, value);

      }

    },

    broker_factory: function (host) {

      return new CustomBroker(host, datafeed);

    },

    broker_config: {

      configFlags: {

        supportLevel2Data: true,

        supportClosePosition: true,

        showQuantityInsteadOfAmount: true,

        supportEditAmount: false,

        supportOrderBrackets: true,

        supportPositionBrackets: true

      }

    }

  }));

}

​

window.addEventListener("DOMContentLoaded", initOnReady, false);

​