Expo create custom plugin

app.config.ts

import type { ConfigContext, ExpoConfig } from "@expo/config";

const defineConfig = (_: ConfigContext): ExpoConfig => ({
  name: "My project",
  slug: "my-project",
  plugins: [
    ["./plugins/mylibrary.plugin.js"],
  ],
});

export default defineConfig;

mylibrary.plugin.js

const {
  withAppBuildGradle,
  withProjectBuildGradle,
} = require("expo/config-plugins");

module.exports = (config) => {
  config = withProjectBuildGradle(config, (config) => {
    const projectGradle = config.modResults;

    // Add kotlin plugins
    projectGradle.contents = projectGradle.contents.replace(
      "dependencies {",
      'dependencies {\n\t\tclasspath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"'
    );
    return config;
  });
  config = withAppBuildGradle(config, (config) => {
    const appGradle = config.modResults;
    // Add kotlin plugins
    appGradle.contents = appGradle.contents.replace(
      'apply plugin: "com.android.application"',
      'apply plugin: "com.android.application"\napply plugin: "kotlin-android"\napply plugin: "kotlin-kapt"'
    );
    // Add databinding
    appGradle.contents = appGradle.contents.replace(
      "android {",
      "android {\n\tbuildFeatures {\n\t\tdataBinding true\n\t}"
    );
    return config;
  });
  return config;
};