plugins-loader.ts

import { join } from 'path';
import * as ts from 'typescript';
import { CLI_ERRORS } from '../../ui';
import { ReadonlyVisitor } from '../interfaces/readonly-visitor.interface';

const PLUGIN_ENTRY_FILENAME = 'plugin';

type Transformer = ts.TransformerFactory<any> | ts.CustomTransformerFactory;
type PluginEntry = string | PluginAndOptions;
type PluginOptions = Record<string, any>;

interface PluginAndOptions {
  name: 'string';
  options: PluginOptions;
}

export interface NestCompilerPlugin {
  before?: (options?: PluginOptions, program?: ts.Program) => Transformer;
  after?: (options?: PluginOptions, program?: ts.Program) => Transformer;
  afterDeclarations?: (
    options?: PluginOptions,
    program?: ts.Program,
  ) => Transformer;
  ReadonlyVisitor?: { new (options: PluginOptions): ReadonlyVisitor };
}

export interface MultiNestCompilerPlugins {
  beforeHooks: Array<(program?: ts.Program) => Transformer>;
  afterHooks: Array<(program?: ts.Program) => Transformer>;
  afterDeclarationsHooks: Array<(program?: ts.Program) => Transformer>;
  readonlyVisitors: Array<ReadonlyVisitor>;
}

export class PluginsLoader {
  public load(
    plugins: PluginEntry[] = [],
    extras: { pathToSource?: string } = {},
  ): MultiNestCompilerPlugins {
    const pluginNames = plugins.map((entry) =>
      typeof entry === 'object'
        ? (entry as PluginAndOptions).name
        : (entry as string),
    );
    const pluginRefs = this.resolvePluginReferences(pluginNames);
    const multiCompilerPlugins: MultiNestCompilerPlugins = {
      afterHooks: [],
      afterDeclarationsHooks: [],
      beforeHooks: [],
      readonlyVisitors: [],
    };

    pluginRefs.forEach((plugin, index) => {
      if (!plugin.before && !plugin.after && !plugin.afterDeclarations) {
        throw new Error(CLI_ERRORS.WRONG_PLUGIN(pluginNames[index]));
      }
      const options =
        typeof plugins[index] === 'object'
          ? (plugins[index] as PluginAndOptions).options || {}
          : {};

      if (plugin.before) {
        multiCompilerPlugins.beforeHooks.push(
          plugin.before.bind(plugin.before, options),
        );
      }

      if (plugin.after) {
        multiCompilerPlugins.afterHooks.push(
          plugin.after.bind(plugin.after, options),
        );
      }

      if (plugin.afterDeclarations) {
        multiCompilerPlugins.afterDeclarationsHooks.push(
          plugin.afterDeclarations.bind(plugin.afterDeclarations, options),
        );
      }

      if (plugin.ReadonlyVisitor) {
        const instance = new plugin.ReadonlyVisitor({
          ...options,
          ...extras,
          readonly: true,
        });
        instance.key = pluginNames[index];
        multiCompilerPlugins.readonlyVisitors.push(instance);
      }
    });
    return multiCompilerPlugins;
  }

  private resolvePluginReferences(pluginNames: string[]): NestCompilerPlugin[] {
    const nodeModulePaths = [
      join(process.cwd(), 'node_modules'),
      ...module.paths,
    ];

    return pluginNames.map((item) => {
      try {
        try {
          const binaryPath = require.resolve(
            join(item, PLUGIN_ENTRY_FILENAME),
            {
              paths: nodeModulePaths,
            },
          );
          return require(binaryPath);
        } catch {}

        const binaryPath = require.resolve(item, { paths: nodeModulePaths });
        return require(binaryPath);
      } catch (e) {
        throw new Error(`"${item}" plugin is not installed.`);
      }
    });
  }
}