PriceAuthority Object

We rely on PriceAuthority oracles. A PriceAuthority gives reliable quotes for prices. The quotes might be based on broad surveys of prices across the ecosystem, or might come directly from an AMM (Automatic Market Maker). A PriceAuthority can either give a quote for the current price across any pair of currencies it knows about, or can immediately return a Promise resolved when a condition is true. For example, a price crossing some threshold, or at a particular time. It can also provide a price feed that updates with every price change.

E(PriceAuthority).getQuoteIssuer(brandIn, brandOut)

• brandIn: Brand
• brandOut: Brand
• Returns: Issuer | Promise<Issuer>

Gets the ERTP Issuer of PriceQuotes for a given brandIn/brandOut pair.

const quoteIssuer = await E(PriceAuthority).getQuoteIssuer(
  collateralKit.brand,
  loanKit.brand
);

E(PriceAuthority).getTimerService(brandIn, brandOut)

• brandIn: Brand
• brandOut: Brand
• Returns: TimerService | Promise<TimerService>

Gets the timer used in PriceQuotes for a given brandIn/brandOut pair.

const myTimer = E(PriceAuthority).getTimerService(
  collateral.brand,
  loanKit.brand
);

E(PriceAuthority).makeQuoteNotifier(amountIn, brandOut)

• amountIn: Amount
• brandOut: Brand
• Returns: ERef<Notifier<PriceQuote>>

Be notified of the latest PriceQuotes for a given amountIn. The issuing rate may be very different between PriceAuthorities.

const myNotifier = E(PriceAuthority).makeQuoteNotifier(quatloos100, usdBrand);

E(PriceAuthority).quoteGiven(amountIn, brandOut)

• amountIn: Amount
• brandOut: Brand
• Returns: Promise<PriceQuote>

Gets a quote on-demand corresponding to amountIn.

const quote = await E(PriceAuthority).quoteGiven(moola500, quatloosBrand);

E(PriceAuthority).quoteWanted(brandIn, amountOut)

• brandIn: Brand
• amountOut: Amount
• Returns: Promise<PriceQuote>

Gets a quote on-demand corresponding to amountOut.

const quote = await E(PriceAuthority).quoteWanted(quatloosBrand, moola500);

E(PriceAuthority).quoteAtTime(deadline, amountIn, brandOut)

• deadline: Timestamp
• amountIn: Amount
• brandOut: Brand
• Returns: Promise<PriceQuote>

Resolves after deadline passes on the PriceAuthority’s timerService with the PriceQuote of amountIn at that time. Note that deadline's value is a BigInt.

const priceQuoteOnThisAtTime = E(PriceAuthority).quoteAtTime(
  7n,
  quatloosAmount34,
  usdBrand
);

E(PriceAuthority).quoteWhenGT(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<PriceQuote>

Resolves when a PriceQuote of amountIn exceeds amountOutLimit.

const quote = E(PriceAuthority).quoteWhenGT(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).quoteWhenGTE(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<PriceQuote>

Resolves when a PriceQuote of amountIn reaches or exceeds amountOutLimit.

const quote = E(PriceAuthority).quoteWhenGTE(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).quoteWhenLT(amountIn, amountOutLimit)

• amountIn Amount
• amountOutLimit Amount
• Returns: Promise<PriceQuote>

Resolves when a PriceQuote of amountIn drops below amountOutLimit.

const quote = E(PriceAuthority).quoteWhenLT(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).quoteWhenLTE(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<PriceQuote>

Resolves when a PriceQuote of amountIn reaches or drops below amountOutLimit.

const quote = E(PriceAuthority).quoteWhenLTE(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).mutableQuoteWhenGT(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<MutableQuote>

Resolves when a PriceQuote of amountIn exceeds amountOutLimit.

const quote = E(PriceAuthority).mutableQuoteWhenGT(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).mutableQuoteWhenGTE(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<MutableQuote>

Resolves when a PriceQuote of amountIn reaches or exceeds amountOutLimit.

const quote = E(PriceAuthority).mutableQuoteWhenGTE(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).mutableQuoteWhenLT(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<MutableQuote>

Resolves when a PriceQuote of amountIn drops below amountOutLimit.

const quote = E(PriceAuthority).mutableQuoteWhenLT(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

E(PriceAuthority).mutableQuoteWhenLTE(amountIn, amountOutLimit)

• amountIn: Amount
• amountOutLimit: Amount
• Returns: Promise<MutableQuote>

Resolves when a PriceQuote of amountIn reaches or drops below amountOutLimit.

const quote = E(PriceAuthority).mutableQuoteWhenLTE(
  AmountMath.make(brands.In, 29n),
  AmountMath.make(brands.Out, 974n)
);

MutableQuote

A MutableQuote represents a statement from a PriceAuthority as to the current price level at a particular time. The significant content (prices and time) is packaged in the Amount, and repeated in the Payment for veracity.

MutableQuotes should be used when you expect to make multiple calls, replacing the trigger value. If you just need a single quote, and won't change the trigger level, you should use PriceQuotes.

A MutableQuote is an Amount-Payment pair, where the Amount is also the current balance of the Payment.

PriceQuote

A PriceQuote represents a statement from a PriceAuthority as to the current price level at a particular time. The significant content (prices and time) is packaged in the Amount and repeated in the Payment for veracity. A PriceQuote is an Amount-Payment pair, where the Amount is also the current balance of the Payment.

const { quoteAmount, quotePayment } = priceQuote;

PriceQuotes are returned in two forms:

• PriceDescription
  • Always includes amountIn, amountOut, the quote's Timestamp, and the TimerService the Timestamp is relative to.
• PriceDescription wrapped as a QuoteAuthority issued payment.
  • This lets quotes be shared in a format letting others verify the time and values.