[Home](./index.md) > [sip.js](./sip.js.md) > [SessionDialog](./sip.js.sessiondialog.md) > [(constructor)](./sip.js.sessiondialog._constructor_.md) ## SessionDialog.(constructor) Constructs a new instance of the `SessionDialog` class Signature: ```typescript constructor(initialTransaction: InviteClientTransaction | InviteServerTransaction, core: UserAgentCore, state: DialogState, delegate?: SessionDelegate); ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | initialTransaction | InviteClientTransaction | InviteServerTransaction | | | core | UserAgentCore | | | state | DialogState | | | delegate | SessionDelegate | |