write Options ignored in chained batch

[MeirionHughes]

with a custom encoder:

let fooEncoding = {
  encode: (x) => x.message,
  decode: (x) => { return { message: String(x) }; },
  type: "foo",
  buffer: false
}

when you batch with the option to use the encoder:

await new Promise(done =>
  db.batch()
    .put({ message: "john" }, "adams")
    .put({ message: "james" }, "kirk")
    .write({ keyEncoding: fooEncoding }, done));

then iterate:

let it = db.iterator({ keyEncoding: fooEncoding });

while (true) {
  let item = await new Promise((r, x) => {
    it.next((err, key, value) => {
      if (err == null && key === undefined && value === undefined) r();
      if (err != null) x(err);
      r({ key: key, value: value });
    });
  });

  if (item == undefined) break;

  console.log(item);
}

keys is stored as "[object Object]" for both.

If you go through put directly:

  await new Promise((r, x) =>
    db.put(
      { message: "john" }, "adams",
      { keyEncoding: fooEncoding },
      (err) => { if (err) x(err); r() }
    ));

  await new Promise((r, x) =>
    db.put(
      { message: "james" }, "kirk",
      { keyEncoding: fooEncoding },
      (err) => { if (err) x(err); r() }
    ));

OR, use the array batch version:

  await new Promise((r, x) =>
    db.batch([
      { type: "put", key: { message: "john" }, value: "adams" },
      { type: "put", key: { message: "james" }, value: "kirk" }],
      { keyEncoding: fooEncoding },
      (e) => ((e) ? x(e) : r())));

You get the expected result:

{ key: { message: 'james' }, value: 'kirk' }
{ key: { message: 'john' }, value: 'adams' }

[vweevers]

Discussing a general solution in Level/levelup#633.