[NUT-15] MultiPath Melt Quotes

src/CashuWallet.ts

@@ -40,7 +40,9 @@ import {
 	type SendResponse,
 	type SerializedBlindedMessage,
 	type SwapPayload,
-	type Token
+	type Token,
+	MPPOption,
+	MeltQuoteOptions
 } from './model/types/index.js';
 import { SubscriptionCanceller } from './model/types/wallet/websocket.js';
 import {
@@ -671,6 +673,44 @@ class CashuWallet {
 		return meltQuote;
 	}
 
+	/**
+	 * Requests a multi path melt quote from the mint.
+	 * @param invoice LN invoice that needs to get a fee estimate
+	 * @param partialAmount the partial amount of the invoice's total to be paid by this instance
+	 * @returns the mint will create and return a melt quote for the invoice with an amount and fee reserve
+	 */
+	async createMultiPathMeltQuote(
+		invoice: string,
+		partialAmount: number
+	): Promise<MeltQuoteResponse> {
+		const { supported, params } = this.mintInfo.isSupported(15);
+		if (!supported) {
+			throw new Error('Mint does not support NUT-15');
+		}
+		if (
+			!params?.filter((method) => {
+				if (method.method === 'bolt11' && method.unit === this.unit) {
+					return true;
+				}
+			}).length
+		) {
+			throw new Error(`Mint does not support MPP for bolt11 and ${this.unit}`);
+		}
+		const mppOption: MPPOption = {
+			amount: partialAmount
+		};
+		const meltOptions: MeltQuoteOptions = {
+			mpp: mppOption
+		};
+		const meltQuotePayload: MeltQuotePayload = {
+			unit: this._unit,
+			request: invoice,
+			options: meltOptions
+		};
+		const meltQuote = await this.mint.createMeltQuote(meltQuotePayload);
+		return meltQuote;
+	}
+
 	/**
 	 * Return an existing melt quote from the mint.
 	 * @param quote ID of the melt quote

src/model/types/wallet/payloads.ts

@@ -48,6 +48,24 @@ export type MeltQuotePayload = {
 	 * Request to be melted to
 	 */
 	request: string;
+	/**
+	 * Melt Quote options (e.g. multi-path payments NUT-15)
+	 */
+	options?: MeltQuoteOptions;
+};
+
+/**
+ * Melt quote specific options
+ */
+export type MeltQuoteOptions = {
+	mpp: MPPOption;
+};
+
+/**
+ * Multi path payments option
+ */
+export type MPPOption = {
+	amount: number;
 };
 
 /**