API Reference

Lightweight quick-reference for mypos-online-checkout. For full examples see Sample Code.

Configuration

Pass a config object to MyPOSClient or supply individual environment variables.

Option	Type	Description
`storeId`	`string`	Your merchant store ID
`storePassword`	`string`	Store password from the merchant portal
`keyIndex`	`number`	Key index (e.g., `1`)
`privateKey`	`string`	RSA private key (PEM format)
`publicKey`	`string`	myPOS public key (PEM format)
`isSandbox`	`boolean`	`true` for the sandbox environment

Equivalent environment variables:

Method	Parameters	Returns	Description
`generateCheckoutFields(opts)`	`CheckoutOptions`	`Promise<Record<string, string>>`	Generate signed fields for hosted-page form submission
`validateNotification(params)`	`Record<string, string>`	`Promise<Result<NotificationData>>`	Validate and parse a payment webhook
`getTransactionStatus(opts)`	`{ orderId: string }`	`Promise<Result<TransactionStatus>>`	Query transaction status by order ID
`refund(opts)`	`RefundOptions`	`Promise<Result<void>>`	Issue full or partial refund
`reversal(opts)`	`ReversalOptions`	`Promise<Result<void>>`	Void a transaction before settlement
`iaPurchase(opts)`	`IAPurchaseOptions`	`Promise<Result<IAPurchaseData>>`	Charge a stored card token directly
`iaPreAuthorization(opts)`	`IAPreAuthOptions`	`Promise<Result<IAPreAuthData>>`	Pre-authorize against a stored token
`preAuthorizationCompletion(opts)`	`PreAuthCompletionOptions`	`Promise<Result<void>>`	Capture a pre-authorization

checkoutUrl — string property on MyPOSClient instance; the target URL for hosted-page form POST.

Most methods return a Result<T> discriminated union — check result.success before accessing data:

if (result.success) {
  // result.data is typed T
} else {
  // result.error contains the failure reason
  console.error(result.error)
}

Only generateCheckoutFields() and validateNotification() can throw — see Error Types below.

Error type	Thrown by	Condition
`MyPOSConfigError`	`new MyPOSClient()`, `generateCheckoutFields()`	Missing or invalid configuration
`MyPOSSignatureError`	`validateNotification()`	Signature on incoming notification does not match
`MyPOSCartError`	`refund()`, `reversal()`, cart-related methods	Cart construction or transaction operation failure

Prop	Type	Required	Description
`checkoutFields`	`Record<string, string>`	Yes	Signed fields from `generateCheckoutFields()`
`checkoutUrl`	`string`	Yes	Form POST target URL (`client.checkoutUrl`)
`submitLabel`	`string`	No	Button text (default: `'Pay'`)
`className`	`string`	No	CSS class on the form element
`autoSubmit`	`boolean`	No	Submit automatically on mount (default: `false`)

Property	Type	Description
`formRef`	`React.RefObject<HTMLFormElement>`	Attach to a `<form>` element
`submit`	`() => void`	Programmatically trigger form submission
`isSubmitting`	`boolean`	`true` while the form is being submitted