Snake Case Naming Strategy for TypeORM

00-usage.md

createConnection({
  [...]
  namingStrategy: new NamingStrategy()
})

naming-strategy.ts

import { DefaultNamingStrategy } from 'typeorm';
import { snakeCase } from 'typeorm/util/StringUtils';

export default class NamingStrategy extends DefaultNamingStrategy {
  public tableName(className: string, customName: string): string {
    return customName || snakeCase(className);
  }

  public columnName(
    propertyName: string,
    customName: string,
    embeddedPrefixes: string[]
  ): string {
    return `${snakeCase(embeddedPrefixes.join('_'))}${customName ||
      snakeCase(propertyName)}`;
  }

  public relationName(propertyName: string): string {
    return snakeCase(propertyName);
  }

  public joinColumnName(
    relationName: string,
    referencedColumnName: string
  ): string {
    return snakeCase(`${relationName}_${referencedColumnName}`);
  }

  public joinTableName(
    firstTableName: string,
    secondTableName: string,
    firstPropertyName: string
  ): string {
    return snakeCase(
      `${firstTableName}_${firstPropertyName.replace(
        /\./gi,
        '_'
      )}_${secondTableName}`
    );
  }

  public joinTableColumnName(
    tableName: string,
    propertyName: string,
    columnName?: string
  ): string {
    return snakeCase(`${tableName}_${columnName || propertyName}`);
  }

  public classTableInheritanceParentColumnName(
    parentTableName: any,
    parentTableIdPropertyName: any
  ): string {
    return snakeCase(`${parentTableName}_${parentTableIdPropertyName}`);
  }
}