Add Typescript Support

.editorconfig

@@ -0,0 +1,20 @@
+# EditorConfig helps developers define and maintain consistent
+# coding styles between different editors and IDEs
+# editorconfig.org
+
+root = true
+
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+
+[*.hbs]
+insert_final_newline = false
+
+[*.{diff,md}]
+trim_trailing_whitespace = false

.eslintignore

@@ -0,0 +1,3 @@
+node_modules
+tmp
+dist

.eslintrc.js

@@ -0,0 +1,39 @@
+"use strict";
+
+module.exports = {
+  root: true,
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: "module",
+  },
+  plugins: ["@typescript-eslint"],
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/eslint-recommended",
+    "plugin:@typescript-eslint/recommended",
+  ],
+  env: {
+    node: true,
+  },
+  rules: {
+    "quotes": "off", // note you must disable the base rule as it can report incorrect errors
+    "no-unused-vars": "off", // note you must disable the base rule as it can report incorrect errors
+    "@typescript-eslint/quotes": ["error", "double"],
+    "@typescript-eslint/no-use-before-define": "off",
+  },
+  overrides: [
+    {
+      files: ["test/**/*.js"],
+      plugins: ["mocha"],
+      env: {
+        mocha: true,
+      },
+      rules: {
+        "mocha/no-exclusive-tests": "error",
+        "mocha/handle-done-callback": "error",
+        "@typescript-eslint/no-var-requires": "off"
+      },
+    },
+  ],
+};

.gitignore

@@ -1,3 +1,9 @@
-node_modules
-test/tmp
-tmp
+# jetbrains
+/.idea/
+/*.iml
+
+# other
+/node_modules
+/test/tmp
+/tmp
+/dist

package.json

@@ -3,7 +3,8 @@
   "description": "Broccoli plugin to merge multiple trees into one",
   "version": "4.2.0",
   "author": "Jo Liss <[email protected]>",
-  "main": "index.js",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "license": "MIT",
   "repository": {
     "type": "git",
@@ -14,27 +15,39 @@
     "merge",
     "copy"
   ],
-  "files": [
-    "index.js"
-  ],
-  "engines": {
-    "node": "10.* || >= 12.*"
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist",
+    "lint": "eslint src test",
+    "lint:fix": "eslint --fix src test",
+    "test": "yarn build && mocha",
+    "test:debug": "yarn build && mocha --inspect-brk",
+    "watch": "tsc --watch"
   },
   "dependencies": {
     "broccoli-plugin": "^4.0.2",
     "merge-trees": "^2.0.0"
   },
   "devDependencies": {
+    "@types/node": "12.12.6",
+    "@typescript-eslint/eslint-plugin": "^2.28.0",
+    "@typescript-eslint/parser": "^2.28.0",
     "broccoli-fixture": "^1.0.0",
+    "broccoli-node-api": "^1.7.0",
     "broccoli-test-helper": "^2.0.0",
     "chai": "^4.1.2",
+    "eslint": "^6.8.0",
+    "eslint-plugin-mocha": "^6.3.0",
     "mocha": "^7.1.1",
-    "mocha-eslint": "^6.0.0"
+    "mocha-eslint": "^6.0.0",
+    "typescript": "^3.8.3"
   },
-  "scripts": {
-    "test": "mocha",
-    "test:debug": "mocha debug"
+  "engines": {
+    "node": "10.* || >= 12.*"
   },
+  "files": [
+    "src/index.ts"
+  ],
   "volta": {
     "node": "12.16.1",
     "yarn": "1.22.4"

src/index.ts

@@ -0,0 +1,74 @@
+import Plugin from "broccoli-plugin";
+import {default as NodeMergeTrees} from "merge-trees";
+import {InputNode} from "broccoli-node-api";
+
+export interface Options {
+  /**
+   *  By default, broccoli-merge-trees throws an error when a file exists in multiple nodes.
+   *  If you pass { overwrite: true }, the output will contain the version of the file as it exists in
+   *  the last input node that contains it.
+   */
+  overwrite?: boolean;
+  /**
+   * A note to help tell multiple plugin instances apart.
+   */
+  annotation?: string;
+  /**
+   *  A string representing the destination path that merged files will be copied to.
+   */
+  destDir?: string;
+}
+
+/**
+ * Copy multiple trees of files on top of each other, resulting in a single merged tree.
+ */
+export class BroccoliMergeTrees extends Plugin {
+
+  private readonly inputNodes: InputNode[];
+  private readonly options: Options;
+  private mergeTrees: NodeMergeTrees | null;
+
+  constructor(inputNodes: InputNode[], options: Options = {}) {
+    if (!Array.isArray(inputNodes)) {
+      const name = "broccoli-merge-trees:" + (options.annotation ?? "");
+      throw new TypeError(`${name}: Expected array, got: [${inputNodes}]`);
+    }
+    super(inputNodes, {
+      persistentOutput: true,
+      needsCache: false,
+      annotation: options.annotation
+    });
+
+    this.inputNodes = inputNodes;
+    this.options = options;
+    this.mergeTrees = null;
+  }
+
+  build(): void {
+    if (this.mergeTrees === null) {
+      // Defer instantiation until the first build because we only
+      // have this.inputPaths and this.outputPath once we build.
+      const outputPath = `${this.outputPath}${this.options.destDir ? "/" + this.options.destDir : ""}`;
+      this.mergeTrees = new NodeMergeTrees(this.inputPaths, outputPath, {
+        overwrite: this.options.overwrite ?? false,
+        annotation: this.options.annotation
+      });
+    }
+
+    try {
+      this.mergeTrees.merge();
+    } catch (err) {
+      if (err !== null && typeof err === "object") {
+        const nodesList = this.inputNodes.map((node, i) => `  ${i + 1}.  ${node.toString()}`).join("\n");
+        const message = `${this.toString()} error while merging the following:\n${nodesList}`;
+
+        err.message = `${message}\n${err.message}`;
+      }
+      throw err;
+    }
+  }
+}
+
+export default function mergeTrees(inputNodes: InputNode[], options: Options = {}): BroccoliMergeTrees {
+  return new BroccoliMergeTrees(inputNodes, options);
+}