Add support + docs for custom esbuild plugins

Author: ericallam

.changeset/rotten-eggs-occur.md

@@ -0,0 +1,6 @@
+---
+"@trigger.dev/build": patch
+"@trigger.dev/core": patch
+---
+
+Added support for custom esbuild plugins

docs/guides/new-build-system-preview.mdx

@@ -245,6 +245,33 @@ export default defineConfig({
 });
 ```
 
+### esbuild plugins
+
+You can now add esbuild plugins to customize the build process using the `esbuildPlugin` build extension. The example below shows how to automatically upload sourcemaps to Sentry using their esbuild plugin:
+
+```ts
+import { defineConfig } from "@trigger.dev/sdk/v3";
+import { esbuildPlugin } from "@trigger.dev/build/extensions";
+import { sentryEsbuildPlugin } from "@sentry/esbuild-plugin";
+
+export default defineConfig({
+  project: "<project ref>",
+  build: {
+    extensions: [
+      esbuildPlugin(
+        sentryEsbuildPlugin({
+          org: process.env.SENTRY_ORG,
+          project: process.env.SENTRY_PROJECT,
+          authToken: process.env.SENTRY_AUTH_TOKEN,
+        }),
+        // optional - only runs during the deploy command, and adds the plugin to the end of the list of plugins
+        { placement: "last", target: "deploy" }
+      ),
+    ],
+  },
+});
+```
+
 ## Known issues
 
 - Path aliases are not yet support in your `trigger.config.ts` file. To workaround this issue you'll need to rewrite path aliases to their relative paths. (See [this](https://github.com/unjs/jiti/issues/166) and [this](https://knip.dev/reference/known-issues#path-aliases-in-config-files)) for more info.

packages/build/src/extensions/index.ts

@@ -0,0 +1 @@
+export * from "@trigger.dev/core/v3/build";

packages/build/src/extensions/typescript.ts

@@ -1,4 +1,4 @@
-import { BuildExtension, createExtensionForPlugin } from "@trigger.dev/core/v3/build";
+import { BuildExtension, esbuildPlugin } from "@trigger.dev/core/v3/build";
 import type { Plugin } from "esbuild";
 import { readFile } from "node:fs/promises";
 import { readTSConfig } from "pkg-types";
@@ -13,7 +13,7 @@ export type EmitDecoratorMetadataOptions = {
 };
 
 export function emitDecoratorMetadata(options: EmitDecoratorMetadataOptions = {}): BuildExtension {
-  return createExtensionForPlugin(plugin(options));
+  return esbuildPlugin(plugin(options));
 }
 
 function plugin(options: EmitDecoratorMetadataOptions = {}): Plugin {

packages/core/src/v3/build/extensions.ts

@@ -2,10 +2,7 @@ import { BuildManifest, BuildTarget } from "../schemas/build.js";
 import type { Plugin } from "esbuild";
 import { ResolvedConfig } from "./resolvedConfig.js";
 
-export function createExtensionForPlugin(
-  plugin: Plugin,
-  options: RegisterPluginOptions = {}
-): BuildExtension {
+export function esbuildPlugin(plugin: Plugin, options: RegisterPluginOptions = {}): BuildExtension {
   return {
     name: plugin.name,
     onBuildStart(context) {