feat: add --slippage param to spot swap (closes #5)

Author: AaronCQL

docs/spot.md

@@ -54,9 +54,11 @@ jup spot quote --from <mint> --to <mint> --raw-amount 1000000000
 ```bash
 jup spot swap --from SOL --to USDC --amount 1
 jup spot swap --from SOL --to USDC --amount 1 --key mykey
+jup spot swap --from SOL --to USDC --amount 1 --slippage 50
 ```
 
 - `--key` overrides the active key for this transaction
+- `--slippage` sets max slippage in basis points (e.g. `50` = 0.5%). Recommended to be emtpy: Jupiter's Real-Time Slippage Estimation (RTSE) automatically picks an optimal value.
 
 ```js
 // Example JSON response:

src/clients/UltraClient.ts

@@ -8,6 +8,7 @@ type GetOrderRequest = {
   outputMint: string;
   amount: string;
   taker?: string | undefined;
+  slippageBps?: string | undefined;
 };
 
 export type GetOrderResponse = {

src/commands/SpotCommand.ts

@@ -56,6 +56,10 @@ export class SpotCommand {
         "Amount in on-chain units (no decimal conversion)"
       )
       .option("--key <name>", "Key to use for signing")
+      .option(
+        "--slippage <bps>",
+        "Max slippage in basis points (leave empty to use Jupiter's Real-Time Slippage Estimation)"
+      )
       .action((opts) => this.swap(opts));
     spot
       .command("portfolio")
@@ -228,9 +232,17 @@ export class SpotCommand {
     amount?: string;
     rawAmount?: string;
     key?: string;
+    slippage?: string;
   }): Promise<void> {
     Swap.validateAmountOpts(opts);
 
+    if (opts.slippage !== undefined) {
+      const bps = Number(opts.slippage);
+      if (!Number.isInteger(bps) || bps < 0) {
+        throw new Error("--slippage must be a non-negative integer (bps).");
+      }
+    }
+
     const settings = Config.load();
     const signer = await Signer.load(opts.key ?? settings.activeKey);
     const [inputToken, outputToken] = await Promise.all([
@@ -244,6 +256,7 @@ export class SpotCommand {
       outputToken,
       amount: opts.amount,
       rawAmount: opts.rawAmount,
+      slippageBps: opts.slippage,
     });
 
     const networkFee = NumberConverter.fromChainAmount(

src/lib/Swap.ts

@@ -39,6 +39,7 @@ export class Swap {
     outputToken: Token;
     amount?: string;
     rawAmount?: string;
+    slippageBps?: string;
   }): Promise<SwapResult> {
     const { signer, inputToken, outputToken } = opts;
     const inputMultiplier = this.getScaledUiMultiplier(inputToken);
@@ -55,6 +56,7 @@ export class Swap {
           inputMultiplier
         ),
       taker: signer.address,
+      slippageBps: opts.slippageBps,
     });
 
     if (order.error) {