TypeScriptToLua · Perryvw · Mar 20, 2022 · Mar 19, 2022 · Mar 20, 2022
diff --git a/src/index.ts b/src/index.ts
@@ -8,4 +8,4 @@ export { LuaLibFeature } from "./LuaLib";
 export * from "./LuaPrinter";
 export * from "./transformation/context";
 export * from "./transpilation";
-export { ProcessedFile } from "./transpilation/utils";
+export { EmitHost, EmitFile, ProcessedFile } from "./transpilation/utils";
diff --git a/src/transpilation/plugins.ts b/src/transpilation/plugins.ts
@@ -3,7 +3,7 @@ import { EmitHost } from "..";
 import { CompilerOptions } from "../CompilerOptions";
 import { Printer } from "../LuaPrinter";
 import { Visitors } from "../transformation/context";
-import { getConfigDirectory, ProcessedFile, resolvePlugin } from "./utils";
+import { EmitFile, getConfigDirectory, ProcessedFile, resolvePlugin } from "./utils";
 
 export interface Plugin {
     /**
@@ -26,17 +26,28 @@ export interface Plugin {
     beforeTransform?: (program: ts.Program, options: CompilerOptions, emitHost: EmitHost) => ts.Diagnostic[] | void;
 
     /**
-     * This function is called after TypeScriptToLua has translated the input program to Lua.
+     * This function is called after translating the input program to Lua, but before resolving dependencies or bundling.
      */
     afterPrint?: (
         program: ts.Program,
         options: CompilerOptions,
         emitHost: EmitHost,
         result: ProcessedFile[]
     ) => ts.Diagnostic[] | void;
+
+    /**
+     * This function is called after translating the input program to Lua, after resolving dependencies and after bundling.
+     */
+    beforeEmit?: (
+        program: ts.Program,
+        options: CompilerOptions,
+        emitHost: EmitHost,
+        result: EmitFile[]
+    ) => ts.Diagnostic[] | void;
 }
 
-export function getPlugins(program: ts.Program, diagnostics: ts.Diagnostic[], customPlugins: Plugin[]): Plugin[] {
+export function getPlugins(program: ts.Program): { diagnostics: ts.Diagnostic[]; plugins: Plugin[] } {
+    const diagnostics: ts.Diagnostic[] = [];
     const pluginsFromOptions: Plugin[] = [];
     const options = program.getCompilerOptions() as CompilerOptions;
 
@@ -58,5 +69,9 @@ export function getPlugins(program: ts.Program, diagnostics: ts.Diagnostic[], cu
         pluginsFromOptions.push(plugin);
     }
 
-    return [...customPlugins, ...pluginsFromOptions];
+    if (options.tstlVerbose) {
+        console.log(`Loaded ${pluginsFromOptions.length} plugins`);
+    }
+
+    return { diagnostics, plugins: pluginsFromOptions };
 }
diff --git a/src/transpilation/transpile.ts b/src/transpilation/transpile.ts
@@ -4,7 +4,7 @@ import { CompilerOptions, validateOptions } from "../CompilerOptions";
 import { createPrinter } from "../LuaPrinter";
 import { createVisitorMap, transformSourceFile } from "../transformation";
 import { isNonNull } from "../utils";
-import { getPlugins, Plugin } from "./plugins";
+import { Plugin } from "./plugins";
 import { getTransformers } from "./transformers";
 import { EmitHost, ProcessedFile } from "./utils";
 
@@ -23,7 +23,7 @@ export interface TranspileResult {
 export function getProgramTranspileResult(
     emitHost: EmitHost,
     writeFileResult: ts.WriteFileCallback,
-    { program, sourceFiles: targetSourceFiles, customTransformers = {}, plugins: customPlugins = [] }: TranspileOptions
+    { program, sourceFiles: targetSourceFiles, customTransformers = {}, plugins = [] }: TranspileOptions
 ): TranspileResult {
     const options = program.getCompilerOptions() as CompilerOptions;
 
@@ -60,12 +60,6 @@ export function getProgramTranspileResult(
         }
     }
 
-    const plugins = getPlugins(program, diagnostics, customPlugins);
-
-    if (options.tstlVerbose) {
-        console.log(`Successfully loaded ${plugins.length} plugins`);
-    }
-
     for (const plugin of plugins) {
         if (plugin.beforeTransform) {
             const pluginDiagnostics = plugin.beforeTransform(program, options, emitHost) ?? [];

diff --git a/src/transpilation/transpiler.ts b/src/transpilation/transpiler.ts
@@ -4,6 +4,7 @@ import { CompilerOptions, isBundleEnabled } from "../CompilerOptions";
 import { getLuaLibBundle } from "../LuaLib";
 import { normalizeSlashes, trimExtension } from "../utils";
 import { getBundleResult } from "./bundle";
+import { getPlugins } from "./plugins";
 import { resolveDependencies } from "./resolve";
 import { getProgramTranspileResult, TranspileOptions } from "./transpile";
 import { EmitFile, EmitHost, ProcessedFile } from "./utils";
@@ -29,23 +30,31 @@ export class Transpiler {
 
     public emit(emitOptions: EmitOptions): EmitResult {
         const { program, writeFile = this.emitHost.writeFile } = emitOptions;
-        const verbose = (program.getCompilerOptions() as CompilerOptions).tstlVerbose;
-        const { diagnostics, transpiledFiles: freshFiles } = getProgramTranspileResult(
-            this.emitHost,
-            writeFile,
-            emitOptions
-        );
+        const options = program.getCompilerOptions() as CompilerOptions;
+
+        const { diagnostics: getPluginsDiagnostics, plugins } = getPlugins(program);
+
+        const { diagnostics, transpiledFiles: freshFiles } = getProgramTranspileResult(this.emitHost, writeFile, {
+            ...emitOptions,
+            plugins,
+        });
 
         const { emitPlan } = this.getEmitPlan(program, diagnostics, freshFiles);
 
-        if (verbose) {
+        if (options.tstlVerbose) {
             console.log("Emitting output");
         }
 
-        const options = program.getCompilerOptions();
+        for (const plugin of plugins) {
+            if (plugin.beforeEmit) {
+                const beforeEmitPluginDiagnostics = plugin.beforeEmit(program, options, this.emitHost, emitPlan) ?? [];
+                diagnostics.push(...beforeEmitPluginDiagnostics);
+            }
+        }
+
         const emitBOM = options.emitBOM ?? false;
         for (const { outputPath, code, sourceMap, sourceFiles } of emitPlan) {
-            if (verbose) {
+            if (options.tstlVerbose) {
                 console.log(`Emitting ${normalizeSlashes(outputPath)}`);
             }
 
@@ -55,11 +64,11 @@ export class Transpiler {
             }
         }
 
-        if (verbose) {
+        if (options.tstlVerbose) {
             console.log("Emit finished!");
         }
 
-        return { diagnostics, emitSkipped: emitPlan.length === 0 };
+        return { diagnostics: getPluginsDiagnostics.concat(diagnostics), emitSkipped: emitPlan.length === 0 };
     }
 
     protected getEmitPlan(

diff --git a/src/transpilation/utils.ts b/src/transpilation/utils.ts
@@ -24,7 +24,6 @@ interface BaseFile {
 export interface ProcessedFile extends BaseFile {
     fileName: string;
     luaAst?: lua.File;
-    /** @internal */
     sourceMapNode?: SourceNode;
 }
 

diff --git a/test/transpile/__snapshots__/project.spec.ts.snap b/test/transpile/__snapshots__/project.spec.ts.snap
@@ -2,8 +2,8 @@
 
 exports[`should give verbose output 1`] = `
 Array [
+  "Loaded 0 plugins",
   "Parsing project settings",
-  "Successfully loaded 0 plugins",
   "Transforming <cwd>/test/transpile/project/otherFile.ts",
   "Printing <cwd>/test/transpile/project/otherFile.ts",
   "Transforming <cwd>/test/transpile/project/index.ts",

diff --git a/test/transpile/plugins/afterPrint.ts b/test/transpile/plugins/afterPrint.ts
@@ -13,7 +13,7 @@ const plugin: tstl.Plugin = {
         void emitHost;
 
         for (const file of result) {
-            file.code = "-- Commented added by afterPrint plugin\n" + file.code;
+            file.code = "-- Comment added by afterPrint plugin\n" + file.code;
         }
     },
 };

diff --git a/test/transpile/plugins/beforeEmit.ts b/test/transpile/plugins/beforeEmit.ts
@@ -0,0 +1,17 @@
+import * as ts from "typescript";
+import * as tstl from "../../../src";
+
+const plugin: tstl.Plugin = {
+    beforeEmit(program: ts.Program, options: tstl.CompilerOptions, emitHost: tstl.EmitHost, result: tstl.EmitFile[]) {
+        void program;
+        void options;
+        void emitHost;
+
+        for (const file of result) {
+            file.code = "-- Comment added by beforeEmit plugin\n" + file.code;
+        }
+    },
+};
+
+// eslint-disable-next-line import/no-default-export
+export default plugin;
diff --git a/test/transpile/plugins/plugins.spec.ts b/test/transpile/plugins/plugins.spec.ts
@@ -112,6 +112,51 @@ test("afterPrint plugin", () => {
     expect(transpiledFiles).toHaveLength(2);
     for (const f of transpiledFiles) {
         // Expect plugin inserted extra lua at start of file
-        expect(f.lua).toContain("-- Commented added by afterPrint plugin");
+        expect(f.lua).toContain("-- Comment added by afterPrint plugin");
+    }
+});
+
+test("beforeEmit plugin", () => {
+    const { transpiledFiles } = util.testModule`
+        console.log("Hello, World!");
+        [].push(1,2,3); // Use lualib code
+    `
+        .addExtraFile(
+            "extrafile.ts",
+            `
+            console.log("Hello, Mars!");
+        `
+        )
+        .setOptions({ luaPlugins: [{ name: path.join(__dirname, "beforeEmit.ts") }] })
+        .getLuaResult();
+
+    // 2 input files + 1 lualib_bundle
+    expect(transpiledFiles).toHaveLength(3);
+    expect(transpiledFiles.find(f => f.outPath.endsWith("lualib_bundle.lua"))).toBeDefined();
+    for (const f of transpiledFiles) {
+        // Expect plugin inserted extra lua at start of all files including lualib bundle
+        expect(f.lua).toContain("-- Comment added by beforeEmit plugin");
+    }
+});
+
+test("beforeEmit plugin bundle", () => {
+    const { transpiledFiles } = util.testBundle`
+        console.log("Hello, World!");
+        [].push(1,2,3); // Use lualib code
+    `
+        .addExtraFile(
+            "extrafile.ts",
+            `
+            console.log("Hello, Mars!");
+        `
+        )
+        .setOptions({ luaPlugins: [{ name: path.join(__dirname, "beforeEmit.ts") }] })
+        .getLuaResult();
+
+    // 1 lua bundle output
+    expect(transpiledFiles).toHaveLength(1);
+    for (const f of transpiledFiles) {
+        // Expect bundle to be affected by plugin
+        expect(f.lua).toContain("-- Comment added by beforeEmit plugin");
     }
 });