“camelCase” < = > “snake_case” conversion with PostgreSQL and Knex.js https://medium.com/p/956357872fe4

db.js

import knex from 'knex';
import Client from 'knex/lib/dialects/postgres';
import Formatter from 'knex/lib/formatter';

Client.prototype.wrapIdentifier = (value) => {
  if (value === '*') return value;
  const matched = value.match(/(.*?)(\[[0-9]\])/);
  if (matched) return Client.prototype.wrapIdentifier.wrapIdentifier(matched[1]) + matched[2];
  return `"${value.replace(/([A-Z])/g, (_, s) => `_${s.toLowerCase()}`).replace(/"/g, '""')}"`;
};

Formatter.prototype.wrapAsIdentifier = value => `"${(value || '').replace(/"/g, '""')}"`;

export default knex({
  client: Client,
  connection: process.env.DATABASE_URL,
});