@pothos/core/src/refs/input-field.ts

Pothos (formerly GiraphQL) is a plugin based schema builder for creating code-first GraphQL schemas in typescript

import {
  inputFieldShapeKey,
  type PothosInputFieldConfig,
  type PothosTypeConfig,
  type SchemaTypes,
} from '../types';

export class InputFieldRef<Types extends SchemaTypes, T = unknown> {
  kind = 'InputObject' as const;

  fieldName?: string;

  $inferInput!: T;

  [inputFieldShapeKey]!: T;

  protected pendingActions: ((
    config: PothosInputFieldConfig<Types>,
  ) => PothosInputFieldConfig<Types> | undefined)[] = [];

  private initConfig: (name: string, typeConfig: PothosTypeConfig) => PothosInputFieldConfig<Types>;

  private onUseCallbacks = new Set<(config: PothosInputFieldConfig<Types>) => void>();

  constructor(
    initConfig: (name: string, typeConfig: PothosTypeConfig) => PothosInputFieldConfig<Types>,
  ) {
    this.initConfig = initConfig;
  }

  updateConfig(
    cb: (config: PothosInputFieldConfig<Types>) => PothosInputFieldConfig<Types> | undefined,
  ) {
    this.pendingActions.push(cb);
  }

  getConfig(name: string, typeConfig: PothosTypeConfig): PothosInputFieldConfig<Types> {
    const config = this.pendingActions.reduce(
      (config, cb) => cb(config) ?? config,
      this.initConfig(name, typeConfig),
    );

    for (const cb of this.onUseCallbacks) {
      this.onUseCallbacks.delete(cb);
      cb(config);
    }

    return config;
  }

  onFirstUse(cb: (config: PothosInputFieldConfig<Types>) => void) {
    this.onUseCallbacks.add(cb);
  }
}