Mutate, set or change values deep within documents

const fetch = require("node-fetch");

// set SANITY_PROJECT_ID/SANITY_KEY/SANITY_DATASET in .env file
require("dotenv").config();

// https://www.sanity.io/docs/http-mutations
// https://www.sanity.io/docs/http-patches
// https://www.sanity.io/docs/json-match

async function mutate(mutations) {
  const result = await fetch(
    `https://${process.env.SANITY_PROJECT_ID}.api.sanity.io/v2021-06-07/data/mutate/${process.env.SANITY_DATASET}`,
    {
      headers: {
        "content-type": "application/json",
        Authorization: `Bearer ${process.env.SANITY_KEY}`,
      },
      body: JSON.stringify(mutations),
      method: "POST",
    }
  );

  const json = await result.json();
  return json;
}

const mutations = {
  mutations: [
    {
      patch: {
        id: "373a5de5-3d0e-4146-bbaa-1a38a26a447d",
        set: {
          '[_id == "373a5de5-3d0e-4146-bbaa-1a38a26a447d"].alternatives[17].title.nn':
            "Noreg",
        },
      },
    },
  ],
};

mutate(mutations);