@thi.ng/bidir-index/encode.js

Bi-directional index mapping arbitrary keys to numeric IDs & vice versa

const encodeObject = (index, obj, defaultValue, indexKeys = true) => {
  const keys = Object.keys(obj);
  const ids = indexKeys ? index.addAll(keys) : index.getAll(keys);
  const res = new Array(index.size).fill(defaultValue);
  for (let id of ids) {
    const val = obj[index.getID(id)];
    if (val != null) res[id] = val;
  }
  return res;
};
const encodeObjectIterator = function* (index, objects, defaultValue, indexKeys = true) {
  if (indexKeys) {
    for (let o of objects) index.addAll(Object.keys(o));
  }
  for (let o of objects) {
    yield* encodeObject(index, o, defaultValue, false);
  }
};
const decodeObject = (index, values, defaults) => {
  const res = {};
  for (let [k, id] of index) {
    const val = values[id] ?? defaults?.[k];
    if (val != null) res[k] = val;
  }
  return res;
};
function* decodeObjectIterator(index, values, size, defaults) {
  for (let i = 0, num = values.length; i < num; i += size) {
    yield decodeObject(index, values.slice(i, i + size), defaults);
  }
}
export {
  decodeObject,
  decodeObjectIterator,
  encodeObject,
  encodeObjectIterator
};