API Reference: Functions

Unified Functions

initiatePayment(input)

Dispatches initiation based on input.method.

function initiatePayment(
  input: UnifiedInitiateInput
): Promise<{ url: string; fields: Record<string, string> } | InitiateKhaltiResult>

Parameters:

• input: A discriminated union on method:
  • method: 'esewa': Requires config: EsewaConfig and order: { orderId, amountPaisa, taxPaisa?, servicePaisa?, deliveryPaisa? }.
  • method: 'khalti': Requires config: KhaltiConfig and order: { purchaseOrderId (or orderId), purchaseOrderName, amountPaisa, customerInfo?, amountBreakdown?, extra? }.

Returns:

• For eSewa: { url: string, fields: Record<string, string> } (target form URL and hidden input dictionary).
• For Khalti: { pidx: string, payment_url: string, expires_at: string, expires_in: number }.

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verifyPayment(input)

Dispatches verification based on input.method and returns a normalized PaymentResult.

function verifyPayment(
  input: UnifiedVerifyInput
): Promise<PaymentResult>

Parameters:

• input:
  • method: 'esewa': Requires config, data (base64 string), expectedOrderId, expectedAmountPaisa.
  • method: 'khalti': Requires config, pidx, expectedAmountPaisa, expectedOrderId?.

Returns:

A promise resolving to a normalized PaymentResult:

interface PaymentResult {
  status: "completed" | "pending" | "failed" | "expired" | "canceled";
  amountPaisa: number;
  orderId: string;
  traceId: string | null; // eSewa ref_id or Khalti transaction_id
  raw: unknown;           // Raw provider responses for audit logging
}

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eSewa Dedicated Functions

buildEsewaFields(opts)

function buildEsewaFields(opts: EsewaFieldOpts): {
  url: string;
  fields: Record<string, string>;
}

Constructs the HMAC-SHA256 signature and returns the form action URL and required fields.

verifyEsewaPayment(opts)

function verifyEsewaPayment(opts: VerifyEsewaPaymentOpts): Promise<PaymentResult>

Decodes data, checks HMAC with timingSafeEqual, queries status API, and normalizes output.

signEpayV2(params, secret)

function signEpayV2(
  p: { total_amount: string; transaction_uuid: string; product_code: string },
  secret: string
): string

Calculates ePay v2 Base64 digest of total_amount=...,transaction_uuid=...,product_code=....

checkEpayStatus(opts)

function checkEpayStatus(opts: EpayStatusOpts): Promise<EpayStatusResult>

Queries eSewa transaction status endpoint directly via HTTP GET.

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Khalti Dedicated Functions

initiateKhalti(opts)

function initiateKhalti(opts: InitiateKhaltiOpts): Promise<InitiateKhaltiResult>

Calls /epayment/initiate/ with Authorization: Key <secret> and returns pidx and payment_url.

lookupKhalti(opts)

function lookupKhalti(opts: LookupKhaltiOpts): Promise<LookupKhaltiResult>

Calls /epayment/lookup/ with pidx. Correctly parses HTTP 400 error bodies into status strings.

verifyKhaltiPayment(opts)

function verifyKhaltiPayment(opts: VerifyKhaltiPaymentOpts): Promise<PaymentResult>

Queries lookup and normalizes payment status to PaymentResult.

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Money Utilities

nprToPaisa(npr: number): number

Converts rupees to integer paisa: Math.round(npr * 100).

paisaToRupeesString(paisa: number): string

Converts integer paisa to string decimal representation (e.g. 12345 $\rightarrow$ "123.45").

parseAmountToPaisa(raw: string | number): number

Parses formatted or comma-separated amount strings (e.g. "1,000.0") to integer paisa (100000).