IDatafeedChartApi
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
OptionalThe 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
OptionalThis function is called if configuration flag supports_time is set to true when chart needs to know the server time.
The library expects callback to be called once.
The time is provided without milliseconds. Example: 1445324591. It is used to display Countdown on the price scale.
Signature
getServerTime(callback: ServerTimeCallback) => void
Parameters
| Name | Type |
|---|---|
| callback | ServerTimeCallback |
Returns
void
getTimescaleMarks
OptionalThe 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
OptionalThe 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
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
OptionalTrading Platform calls this function when it wants to receive real-time level 2 (DOM) for a symbol.
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
OptionalTrading Platform calls this function when it doesn't want to receive updates for this listener anymore.
Signature
unsubscribeDepth(subscriberUID: string) => void
Parameters
| Name | Type | Description |
|---|---|---|
| subscriberUID | string | A string returned by subscribeDepth |
Returns
void