makeAddInflectorsPlugin (graphile-utils)

NOTE: this documentation applies to PostGraphile v4.1.0+

If you're not happy with the default naming conventions in PostGraphile (or if you want to extend PostGraphile's functionality and use the inflection system to do so), you can use makeAddInflectorsPlugin from graphile-utils.

Please see the inflection article for more information on inflection in PostGraphile.

Syntax

interface Inflectors {
  [str: string]: (...args: Array<any>) => string;
}

type InflectorsGenerator = (
  inflection: Inflectors,
  build: Build,
  options: Options,
) => Inflectors;

function makeAddInflectorsPlugin(
  additionalInflectorsOrGenerator: Inflectors | InflectorsGenerator,
  replace = false,
): Plugin;

By default, this plugin is for adding new inflectors; however if you pass true as the second argument then it can be used for replacing (or wrapping) existing inflectors.

You can pass either a new inflectors object to makeAddInflectorsPlugin, or if you need to call the previous inflector you're replacing then you can pass an "inflectors generator" function which will be passed the whole inflectors object. NOTE: your new inflectors will be merged into this object, so if you need to call the old inflectors from the new ones you must take a copy of them which you can do with "dereferencing," but be sure to use .call(this, ...) to keep the this binding correct; e.g.:

const { makeAddInflectorsPlugin } = require("graphile-utils");

module.exports = makeAddInflectorsPlugin((inflectors) => {
  // Here 'enumName' is dereferenced to 'oldEnumName' from the existing
  // inflectors.
  const { enumName: oldEnumName } = inflectors;

  return {
    enumName(value: string) {
      // By the time we get here, `inflectors.enumName` refers to this very
      // method, so we must call `oldEnumName` rather than
      // `inflectors.enumName` otherwise we will get a "Maximum call stack size
      // exceeded" error.

      // Further, we must ensure that the value of `this` is passed through
      // otherwise the old inflector cannot reference other inflectors.

      return oldEnumName.call(this, value.replace(/\./g, "_"));
    },
  };
}, true);

Example

If you want *Patch types to instead be called *ChangeSet you could make a plugin such as this one:

// MyInflectionPlugin.js
const { makeAddInflectorsPlugin } = require("graphile-utils");

module.exports = makeAddInflectorsPlugin(
  {
    patchType(typeName: string) {
      return this.upperCamelCase(`${typeName}-change-set`);
    },
  },
  /* Passing true here allows the plugin to overwrite
   * existing inflectors.
   */
  true,
);

// Load this plugin with `postgraphile --append-plugins /path/to/MyInflectionPlugin.js`

Where are the default inflectors defined?

The default Graphile Engine inflectors (pluralize, singularize, upperCamelCase, camelCase and constantCase) can be found in makeNewBuild.js.

The additional inflectors used in PostGraphile can be found in PgBasicsPlugin.js, but also some other places There's a lot of them!