Refactor to improve types

Reviewed-by: Merlijn Vos <merlijn@soverin.net>
Reviewed-by: Christian Murphy <christian.murphy.42@gmail.com>

Related to GH-6.
Closes GH-7.

index.js

@@ -1,6 +1,7 @@
 'use strict'
+
 /**
- * @typedef {import('unified').FrozenProcessor} FrozenProcessor
+ * @typedef {import('unified').Processor} Processor
  * @typedef {import('unified').RunCallback} RunCallback
  * @typedef {import('unified').Transformer} Transformer
  * @typedef {import('unist').Node} Node
@@ -15,40 +16,33 @@ var hast2mdast = require('hast-util-to-mdast')
  * tree (bridge-mode). Without destination, returns the mdast tree: further
  * plugins run on that tree (mutate-mode).
  *
+ * @param destination Optional unified processor.
+ * @param options Options passed to `hast-util-to-mdast`.
  */
-var attacher =
+module.exports =
   /**
-   * @type {(
-   *   ((destination?: FrozenProcessor, options?: Options) => Transformer) &
-   *   ((options?: Options) => Transformer)
-   * )}
+   * @type {import('unified').Plugin<[Options?]|[Processor, Options?]>}
    */
   (
     /**
-     * @param {FrozenProcessor | Options} [destination]
+     * @param {Processor|Options} [destination]
      * @param {Options} [options]
      */
     function (destination, options) {
-      /** @type {Options | undefined} */
+      /** @type {Options|undefined} */
       var settings
-      /** @type {FrozenProcessor | undefined} */
+      /** @type {Processor|undefined} */
       var processor
 
-      if (
-        destination &&
-        !(/** @type {FrozenProcessor} */ (destination).process)
-      ) {
-        // Overload: 'options' passed to first parameter
-        settings = /** @type {Options} */ (destination)
-        destination = null
+      if (typeof destination === 'function') {
+        processor = destination
+        settings = options || {}
       } else {
-        processor = /** @type {FrozenProcessor | undefined} */ (destination)
+        settings = destination || {}
       }
 
-      settings = settings || options || {}
-
       if (settings.document === undefined || settings.document === null) {
-        settings.document = true
+        settings = Object.assign({}, settings, {document: true})
       }
 
       return processor ? bridge(processor, settings) : mutate(settings)
@@ -58,7 +52,7 @@ var attacher =
 /**
  * Bridge-mode.
  * Runs the destination with the new mdast tree.
- * @param {FrozenProcessor} destination
+ * @param {Processor} destination
  * @param {Options} [options]
  * @returns {Transformer}
  */
@@ -69,12 +63,9 @@ function bridge(destination, options) {
     destination.run(hast2mdast(node, options), file, done)
     /** @type {RunCallback} */
     function done(err) {
-      // Cast to proper type - remove when upstream typing of Transformer is fixed.
-      // Note: `next` only requires one parameter: https://github.com/unifiedjs/unified#function-nexterr-tree-file
-      var typefixedNext =
-        /** @type {(error: Error | null, node?: Node, file?: import('vfile').VFile) => void} */
-        (next)
-      typefixedNext(err)
+      // @ts-expect-error: `unified` should accept 1 arg for next.
+      // See: <https://github.com/unifiedjs/unified/pull/141#issuecomment-871239574>
+      next(err)
     }
   }
 }
@@ -94,8 +85,6 @@ function mutate(options) {
   }
 }
 
-module.exports = attacher
-
 // Remove the following JSDoc block when upgrading hast-util-to-mdast to version 8.
 // Import these types from hast-util-to-mdast when version 8 released.
 /**

package.json

@@ -25,12 +25,16 @@
     "Titus Wormer <tituswormer@gmail.com> (https://wooorm.com)"
   ],
   "dependencies": {
+    "@types/hast": "^2.0.0",
+    "@types/mdast": "^3.0.0",
+    "@types/unist": "^2.0.0",
     "hast-util-to-mdast": "^7.0.0"
   },
   "files": [
     "index.js"
   ],
   "devDependencies": {
+    "@types/tape": "^4.0.0",
     "browserify": "^17.0.0",
     "nyc": "^15.0.0",
     "prettier": "^2.0.0",
@@ -39,6 +43,7 @@
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
     "remark-stringify": "^9.0.0",
+    "rimraf": "^3.0.0",
     "tape": "^5.0.0",
     "tinyify": "^3.0.0",
     "type-coverage": "^2.0.0",
@@ -48,7 +53,7 @@
   },
   "scripts": {
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "build-types": "tsc -b && type-coverage",
+    "build-types": "rimraf \"*.d.ts\" && tsc && type-coverage",
     "build-bundle": "browserify . -s rehypeRemark -o rehype-remark.js",
     "build-mangle": "browserify . -s rehypeRemark -o rehype-remark.min.js -p tinyify",
     "build": "npm run build-types && npm run build-bundle && npm run build-mangle",
@@ -86,6 +91,9 @@
     "atLeast": 100,
     "detail": true,
     "strict": true,
-    "ignoreCatch": true
+    "ignoreCatch": true,
+    "ignoreFiles": [
+      "index.d.ts"
+    ]
   }
 }

test.js

@@ -1,5 +1,12 @@
 'use strict'
 
+/**
+ * @typedef {import('./index.js').Options} Options
+ * @typedef {import('./index.js').Handle} Handle
+ * @typedef {import('hast').Element} Element
+ * @typedef {import('hast').Text} Text
+ */
+
 var test = require('tape')
 var unified = require('unified')
 var parse = require('rehype-parse')
@@ -60,12 +67,19 @@ test('rehype2remark()', function (t) {
 })
 
 test('handlers option', function (t) {
+  /** @type {Options} */
   var options = {
     handlers: {
+      /**
+       * @type {Handle}
+       * @param {Element & {tagName: 'div'}} node
+       */
       div: function (h, node) {
-        node.children[0].value = 'changed'
-        node.type = 'paragraph'
-        return h(node, 'paragraph', node.children)
+        /** @type {Text} */
+        // @ts-expect-error: there’s one text child.
+        const child = node.children[0]
+        child.value = 'changed'
+        return h(node, 'paragraph', child)
       }
     }
   }

tsconfig.json

@@ -3,7 +3,6 @@
     "*.js"
   ],
   "exclude": [
-    "test.js",
     "rehype-remark.js",
     "*.min.js"
   ],
@@ -18,5 +17,7 @@
     "checkJs": true,
     "declaration": true,
     "emitDeclarationOnly": true,
+    "allowSyntheticDefaultImports": true,
+    "skipLibCheck": true
   }
 }