Plugins

TypeScriptToLua supports plugins - an interface that allows to customize transpilation behavior.

To add a plugin you have to add it under tstl.luaPlugins option in the configuration file.

Example:

tsconfig.json

{

"tstl": {

"luaPlugins": [

// Plugin is a JavaScript module exporting an object

{ "name": "./plugin1.js" },

// TypeScriptToLua can load plugins written in TypeScript using `ts-node`

{ "name": "./plugin2.ts" },

// Plugins can be published to npm

{ "name": "tstl-plugin-3" }

]

}

}

API

visitors

Internally, to process Abstract Syntax Tree of a TypeScript program, TypeScriptToLua implements the visitor pattern. Visitor is a function, called with a processed node and transformation context, and returning a Lua AST node. Plugins can inject their own visitors using visitors property, overriding standard transformation behavior.

Example:

import * as ts from "typescript";

import * as tstl from "typescript-to-lua";

const plugin: tstl.Plugin = {

// `visitors` is a record where keys are TypeScript node syntax kinds

visitors: {

// Visitor can be a function that returns Lua AST node

[ts.SyntaxKind.ReturnStatement]: () => tstl.createReturnStatement([tstl.createBooleanLiteral(true)]),

},

};

export default plugin;

Example 2:

import * as ts from "typescript";

import * as tstl from "typescript-to-lua";

const plugin: tstl.Plugin = {

visitors: {

// Visit string literals, if original transformer returns a string literal, change the string to "bar" instead

[ts.SyntaxKind.StringLiteral]: (node, context) => {

// `context` exposes `superTransform*` methods, that can be used to call either the visitor provided by previous

// plugin, or a standard TypeScriptToLua visitor

const result = context.superTransformExpression(node);

// Standard visitor for ts.StringLiteral always returns tstl.StringLiteral node

if (tstl.isStringLiteral(result)) {

result.value = "bar";

}

return result;

},

},

};

export default plugin;

printer

Printer is a function that overrides standard implementation of Lua AST printer. It receives some information about the file and transformed Lua AST. See Printer page for more information.

Example:

import * as tstl from "typescript-to-lua";

class CustomLuaPrinter extends tstl.LuaPrinter {}

const plugin: tstl.Plugin = {

printer: (program, emitHost, fileName, block, luaLibFeatures) =>

new CustomLuaPrinter(program.getCompilerOptions(), emitHost, fileName).print(block, luaLibFeatures),

};

export default plugin;