Get change next states

//native

function authHeader(auth: RT.Servicenow) {

  return auth.token

    ? `Bearer ${auth.token}`

    : `Basic ${btoa(`${auth.username}:${auth.password}`)}`

}

/**

 * Get Change Next States

 * List the states a change request can move to next, including its current state, through the Change Management API (GET /api/sn_chg_rest/change/{sys_id}/nextstates, documented in the Yokohama and Brazil API references). For changes driven by a change model, each transition also says whether it is available and which conditions passed or failed; type-driven (legacy) changes only return the state list.

 */

export async function main(auth: RT.Servicenow, sys_id: string) {

  const url = new URL(

    `${auth.instance_url}/api/sn_chg_rest/change/${encodeURIComponent(sys_id)}/nextstates`

  )

  const response = await fetch(url, {

    headers: {

      Authorization: authHeader(auth),

      Accept: "application/json",

    },

  })

  if (!response.ok) {

    throw new Error(`${response.status} ${await response.text()}`)

  }

  const { result } = (await response.json()) as {

    result: {

      available_states?: string[]

      state_label?: { [state: string]: string }

      state_transitions?: any[]

    }

  }

  // The schema documents state_transitions as an array of transitions, but the

  // documented example nests one array per target state: accept both.

  const transitions = (result.state_transitions ?? []).flat().map((t: any) => ({

    from_state: t.from_state,

    to_state: t.to_state,

    to_state_label: result.state_label?.[t.to_state],

    display_value: t.display_value,

    transition_available: t.transition_available,

    automatic_transition: t.automatic_transition,

    conditions: (t.conditions ?? []).map((c: any) => ({

      name: c.condition?.name,

      description: c.condition?.description,

      passed: c.passed,

    })),

  }))

  return {

    available_states: (result.available_states ?? []).map((state) => ({

      state,

      label: result.state_label?.[state],

    })),

    transitions,

    result,

  }

}