variable used before being assigned

报错：Variable 'errMsg' is used before being assigned.ts(2454)

let errMsg: string;
if (err?.code === Code.CANCELED) {
    errMsg = '支付取消';
}
// 这里会报错：Variable 'errMsg' is used before being assigned.ts(2454)
if (errMsg) {
    Hud.Text({ text: errMsg });
}

解决：

let errMsg: string | undefined;