IDatafeedChartApi

Interface

Methods

getBars

This function is called when the chart needs a history fragment defined by dates range.

Signature

getBars(symbolInfo: LibrarySymbolInfo, resolution: ResolutionString, periodParams: PeriodParams, onResult: HistoryCallback, onError: ErrorCallback) => void

Parameters

Name	Type	Description
symbolInfo	LibrarySymbolInfo	A SymbolInfo object
resolution	ResolutionString	Resolution of the symbol
periodParams	PeriodParams	An object used to pass specific requirements for getting bars
onResult	HistoryCallback	Callback function for historical data
onError	ErrorCallback	Callback function whose only argument is a text error message

Returns

​void

---

getMarks

Optional

The library calls this function to get marks for visible bars range. The library assumes that you will call onDataCallback only once per getMarks call.

A few marks per bar are allowed (for now, the maximum is 10). The time of each mark must match the time of a bar. For example, if the bar times are 2023-01-01, 2023-01-08, and 2023-01-15, then a mark cannot have the time 2023-01-05.

Remark: This function will be called only if you confirmed that your back-end is supporting marks (DatafeedConfiguration.supports_marks).

Signature

getMarks(symbolInfo: LibrarySymbolInfo, from: number, to: number, onDataCallback: GetMarksCallback<Mark>, resolution: ResolutionString) => void

Parameters

Name	Type	Description
symbolInfo	LibrarySymbolInfo	A SymbolInfo object
from	number	Unix timestamp (leftmost visible bar)
to	number	Unix timestamp (rightmost visible bar)
onDataCallback	GetMarksCallback<Mark>	Callback function containing an array of marks
resolution	ResolutionString	Resolution of the symbol

Returns

​void

---

getServerTime

Optional

This function is called if the supports_time configuration flag is true when the chart needs to know the server time. The library expects a callback to be called once. The time is provided without milliseconds. Example: 1445324591.

getServerTime is used to display countdown on the price scale. Note that the countdown can be displayed only for intraday resolutions.

Signature

getServerTime(callback: ServerTimeCallback) => void

Parameters

Name	Type
callback	ServerTimeCallback

Returns

​void

---

getTimescaleMarks

Optional

The library calls this function to get timescale marks for visible bars range. The library assumes that you will call onDataCallback only once per getTimescaleMarks call.

Remark: This function will be called only if you confirmed that your back-end is supporting marks (DatafeedConfiguration.supports_timescale_marks).

Signature

getTimescaleMarks(symbolInfo: LibrarySymbolInfo, from: number, to: number, onDataCallback: GetMarksCallback<TimescaleMark>, resolution: ResolutionString) => void

Parameters

Name	Type	Description
symbolInfo	LibrarySymbolInfo	A SymbolInfo object
from	number	Unix timestamp (leftmost visible bar)
to	number	Unix timestamp (rightmost visible bar)
onDataCallback	GetMarksCallback<TimescaleMark>	Callback function containing an array of marks
resolution	ResolutionString	Resolution of the symbol

Returns

​void

---

getVolumeProfileResolutionForPeriod

Optional

The library calls this function to get the resolution that will be used to calculate the Volume Profile Visible Range indicator.

Usually you might want to implement this method to calculate the indicator more accurately. The implementation really depends on how much data you can transfer to the library and the depth of data in your data feed. Remark: If this function is not provided the library uses currentResolution.

Signature

getVolumeProfileResolutionForPeriod(currentResolution: ResolutionString, from: number, to: number, symbolInfo: LibrarySymbolInfo) => ResolutionString

Parameters

Name	Type	Description
currentResolution	ResolutionString	Resolution of the symbol
from	number	Unix timestamp (leftmost visible bar)
to	number	Unix timestamp (rightmost visible bar)
symbolInfo	LibrarySymbolInfo	A Symbol object

Returns

A resolution

​ResolutionString

---

resolveSymbol

The library will call this function when it needs to get SymbolInfo by symbol name.

Signature

resolveSymbol(symbolName: string, onResolve: ResolveCallback, onError: ErrorCallback, extension?: SymbolResolveExtension) => void

Parameters

Name	Type	Description
symbolName	string	Symbol name or ticker
onResolve	ResolveCallback	Callback function returning a SymbolInfo (LibrarySymbolInfo)
onError	ErrorCallback	Callback function whose only argument is a text error message
extension?	SymbolResolveExtension	An optional object with additional parameters

Returns

​void

---

searchSymbols

Provides a list of symbols that match the user's search query.

Signature

searchSymbols(userInput: string, exchange: string, symbolType: string, onResult: SearchSymbolsCallback) => void

Parameters

Name	Type	Description
userInput	string	Text entered by user in the symbol search field
exchange	string	The requested exchange. Empty value means no filter was specified
symbolType	string	Type of symbol. Empty value means no filter was specified
onResult	SearchSymbolsCallback	Callback function that returns an array of results (SearchSymbolResultItem) or empty array if no symbols found

Returns

​void

---

subscribeBars

The library calls this function when it wants to receive real-time updates for a symbol. The library assumes that you will call the callback provided by the onTick parameter every time you want to update the most recent bar or to add a new one.

Signature

subscribeBars(symbolInfo: LibrarySymbolInfo, resolution: ResolutionString, onTick: SubscribeBarsCallback, listenerGuid: string, onResetCacheNeededCallback: Function) => void

Parameters

Name	Type	Description
symbolInfo	LibrarySymbolInfo	A SymbolInfo object
resolution	ResolutionString	Resolution of the symbol
onTick	SubscribeBarsCallback	Callback function returning a Bar object
listenerGuid	string
onResetCacheNeededCallback	() => void	Function to be executed when bar data has changed

Returns

​void

---

subscribeDepth

Optional

Trading Platform calls this function when it wants to receive real-time level 2 (DOM) for a symbol. Note that you should set the BrokerConfigFlags.supportLevel2Data configuration flag to true.

Signature

subscribeDepth(symbol: string, callback: DOMCallback) => string

Parameters

Name	Type	Description
symbol	string	A SymbolInfo object
callback	DOMCallback	Function returning an object to update Depth Of Market (DOM) data

Returns

A unique identifier that will be used to unsubscribe from the data

​string

---

unsubscribeBars

The library calls this function when it doesn't want to receive updates anymore.

Signature

unsubscribeBars(listenerGuid: string) => void

Parameters

Name	Type	Description
listenerGuid	string	id to unsubscribe from

Returns

​void

---

unsubscribeDepth

Optional

Trading Platform calls this function when it doesn't want to receive updates for this listener anymore. Note that you should set the BrokerConfigFlags.supportLevel2Data configuration flag to true.

Signature

unsubscribeDepth(subscriberUID: string) => void

Parameters

Name	Type	Description
subscriberUID	string	A string returned by subscribeDepth

Returns

​void