toTradingViewDatafeed

Adapt a CandleSource into a TradingView Charting Library datafeed.

A pure translation layer: resolution codes, unix-second period params, and the library’s callback style on one side; the SDK’s resolution vocabulary, millisecond timestamps, and promise/Unwatch style on the other. It holds no framework state and imports nothing from TradingView — the datafeed contract is modeled structurally, so the returned object satisfies the library’s own IBasicDataFeed type without the SDK depending on the licensed package.


import { createBinanceCandleSource, toTradingViewDatafeed } from "@symmio/trading-core";
 
const datafeed = toTradingViewDatafeed(createBinanceCandleSource());
 
new TradingView.widget({ datafeed, symbol: "BTCUSDT", interval: "60" });

Parameters

sourceCandleSource

The candle source to read from.

options.exchangestringoptional

Exchange label shown in the chart’s symbol header. Defaults to the source’s id.

options.sessionstringoptional

Session string for the instrument. Defaults to "24x7" — correct for crypto perps, which never close.

options.timezonestringoptional

Timezone the chart renders bar times in. Defaults to "Etc/UTC", matching the UTC-aligned bar boundaries every source returns.

Returns

TradingViewDatafeed

A datafeed object to pass straight to widget({datafeed}) — onReady, searchSymbols, resolveSymbol, getBars, subscribeBars, and unsubscribeBars implemented over the source.

Behavior worth knowing

Symbol search is reported as unsupported. A SYMMIO app already has its market list (useMarkets), and driving symbol selection from that is both more accurate and less surprising than a second search surface here.
countBack wins over from. In the library’s contract countBack is the exact number of bars the chart needs ending at to; the adapter widens the window to at least that many bars so a short from cannot starve the chart.
Reconnects invalidate the chart’s cache. When the source signals a reset, the adapter calls the library’s onResetCacheNeeded, so it refetches history instead of splicing the live bar onto a series with a hole in it.
has_empty_bars is false — the chart leaves real gaps rather than inventing flat bars where the venue reported none.
Live-streaming markets report data_status: "streaming"; a source without watchCandles reports "endofday".

The datafeed owns its live subscriptions, keyed by the library’s listener guid. Keep one instance alive per widget — in React, use useTradingViewDatafeed, which memoizes it.

Resolution mapping

TradingView encodes intraday resolutions as bare minute counts ("60" is one hour), seconds with an S suffix, and days/weeks/months with a letter. Two helpers translate:


import { fromTradingViewResolution, toTradingViewResolution } from "@symmio/trading-core";
 
fromTradingViewResolution("60"); // "1h" — undefined when the code is unrecognized
toTradingViewResolution("1h"); // "60"

The bare-letter forms ("D", "W", "M") are accepted alongside the numbered ones on the way in, because the library emits both depending on how the chart was configured; only one spelling per resolution is advertised on the way out.

Types

Type	What it is
`TradingViewDatafeed`	The datafeed object `widget({ datafeed })` expects.
`TradingViewDatafeedConfiguration`	Capabilities reported from `onReady`.
`TradingViewSymbolInfo`	Symbol metadata returned from `resolveSymbol`.
`TradingViewBar`	A bar in TradingView’s shape — `time` is unix milliseconds.
`TradingViewPeriodParams`	The range and bar count the library asks `getBars` for (unix seconds).
`TradingViewHistoryMetadata`	`{ noData: boolean }` accompanying a `getBars` result.

These are structural types declared by the SDK — the Charting Library is a licensed artifact a consumer self-hosts, so the SDK cannot depend on its types without forcing every consumer to vendor it.

useTradingViewDatafeed — the memoized React wrapper.
Majors chart guide — wiring the widget end to end.
Resolutions — the SDK’s resolution vocabulary.