Getting started

Lexshift helps you work with records whose lexicons change over time. Start with identify to find the revision a record matches, then use shift to migrate it to a target revision.

Install

npm

npm i lexshift

pnpm

pnpm add lexshift

yarn

yarn add lexshift

Identify a record

import { identify } from "lexshift";

const record = {
  $type: "com.example.profile",
  name: "Ada",
};

const result = await identify(record, {
  historyProvider: async ({ nsid, current }) => {
    const history = await loadPreviousLexicons(nsid, current.revision);

    return history.map((candidate) => ({
      revision: candidate.revision,
      lexicon: candidate.lexicon,
      cid: candidate.cid,
    }));
  },
});

console.log(result.revision);

Shift to a new revision

import { shift } from "lexshift";

const migrated = await shift(record, 3, {
  historyProvider: async ({ nsid, current }) => {
    return loadPreviousLexicons(nsid, current.revision).map((candidate) => ({
      revision: candidate.revision,
      lexicon: candidate.lexicon,
    }));
  },
});

console.log(migrated.oldRevision, migrated.newRevision);

Use historyProvider when you want Lexshift to compare the current lexicon with earlier revisions. If the record already matches the current schema, identify returns immediately.