Add JSDoc based types

.gitignore

@@ -1,4 +1,5 @@
 .DS_Store
+*.d.ts
 *.log
 coverage/
 node_modules/

build-iso-3166-1-a2-table.js

@@ -1,8 +1,10 @@
 import unified from 'unified'
+// @ts-ignore To do: remove when types are added
 import format from 'rehype-format'
 import stringify from 'rehype-stringify'
 import h from 'hastscript'
 import u from 'unist-builder'
+// @ts-ignore To do: remove when types are added
 import range from 'mdast-util-heading-range'
 import {iso31661Reserved} from './1-reserved.js'
 import {iso31661} from './1.js'
@@ -12,37 +14,56 @@ var processor = unified().use(format).use(stringify)
 export default function table() {
   return transform
 
+  /**
+   * @param {import('mdast').Root} tree
+   */
   function transform(tree) {
-    var fromCode = String.fromCharCode
     var a = 65
     var z = 90
 
     var a2ToState = {}
     var a2ToName = {}
-    iso31661.concat(iso31661Reserved).forEach((d) => {
-      a2ToState[d.alpha2] = d.state
-      a2ToName[d.alpha2] = d.name
-    })
+    iso31661
+      .map(({alpha2, state, name}) => ({alpha2, state, name}))
+      .concat(
+        iso31661Reserved.map(({alpha2, state, name}) => ({alpha2, state, name}))
+      )
+      .forEach((d) => {
+        a2ToState[d.alpha2] = d.state
+        a2ToName[d.alpha2] = d.name
+      })
 
     range(tree, 'matrix', onrun)
 
-    function onrun(start, nodes, end) {
+    /**
+     * @param {import('unist').Node?} start
+     * @param {import('unist').Node[]} _
+     * @param {import('unist').Node?} end
+     */
+    function onrun(start, _, end) {
       var head = [h('th')]
+      /** @type {import('hast').Element[]} */
       var rows = []
+      /** @type {import('hast').Element[]} */
       var cells
+      /** @type {number} */
       var x = a
+      /** @type {number} */
       var y
+      /** @type {import('hast').Element|string} */
       var code
+      /** @type {string} */
       var state
+      /** @type {string} */
       var title
 
       while (x <= z) {
         y = a
-        head.push(h('th', fromCode(x)))
-        cells = [h('th', {scope: 'row'}, fromCode(x))]
+        head.push(h('th', String.fromCharCode(x)))
+        cells = [h('th', {scope: 'row'}, String.fromCharCode(x))]
 
         while (y <= z) {
-          code = fromCode(x) + fromCode(y)
+          code = String.fromCharCode(x) + String.fromCharCode(y)
           state = a2ToState[code]
           title = a2ToName[code]