add script to check typescript against jsdoc and map back to coffee

desired-output.coffee

@@ -0,0 +1,108 @@
+###
+jsdoc:
+/**
+ * @type {(x: number) => number}
+ * /
+var f;
+
+/**
+ * @param {number} x
+ * @returns {number}
+ * /
+f = function(x) {
+  return x + 3;
+}
+
+.d.ts:
+/**
+ * @type {(x: number) => number}
+ * /
+declare var f: (x: number) => number;
+###
+# f<[=> number]> = (x<[number]>) -> x + 3
+# f<[(x: number) => number]> = (x) -> x + 3
+f = (x) -> x + 3
+
+###
+jsdoc:
+/**
+ * @type {{a: number}}
+ * /
+var x;
+
+x = {
+  a: 3
+};
+
+.d.ts:
+/**
+ * @type {{a: number}}
+ * /
+declare var x: {
+    a: number;
+};
+###
+# x = {a<[number]>: 3}
+# x<[{a: number}]> = {a: 3}
+x = {a: 3}
+
+###
+jsdoc:
+/**
+ * @type {({a}: {a: string}) => string}
+ * /
+var g;
+
+/**
+ * @param {{a: string}} _
+ * @returns {string}
+ * /
+g = function({a: x}) {
+  return x;
+}
+
+.d.ts:
+/**
+ * @type {({a}: {a: string}) => string}
+ * /
+declare var g: ({ a }: {
+    a: string;
+}) => string;
+###
+# g<[=> string]> = ({a<[string]>: x}) -> x
+# this one does not rename the field:
+# g<[=> string]> = ({a<[string]>}) -> a
+g = ({a: x}) -> x
+
+###
+jsdoc:
+/**
+ * @type {({a, b, c, e}: {a: number, b?: number, c: {d?: number}, e: [f: number]}) => number}
+ * /
+var h;
+
+/**
+ * @param {{a: number, b?: number, c: {d?: number}, e: [f: number]}} _
+ * @returns number
+ * /
+h = function({a, b = 3, c: {d = 3}, e: [f]}) {
+  return a + b + d;
+};
+
+.d.ts:
+/**
+ * @type {({a, b, c, e}: {a: number, b?: number, c: {d?: number}, e: [f: number]}) => number}
+ * /
+declare var h: ({ a, b, c, e }: {
+    a: number;
+    b?: number;
+    c: {
+        d?: number;
+    };
+    e: [f: number];
+}) => number;
+###
+# h<[=> number]> = ({a<[number]>, b<[?number]> = 3, c: {d<[?number]> = 3}, e: [f<[number]>]}) ->
+#   a + b + d
+h = ({a, b = 3, c: {d = 3}, e: [f]}) ->
+  a + b + d + f

package.json

@@ -49,6 +49,7 @@
     "jison": "~0.4.18",
     "markdown-it": "~13.0.0",
     "puppeteer": "~13.6.0",
+    "typescript": "^5.6.3",
     "underscore": "~1.13.3",
     "webpack": "~5.72.0"
   }

tsc-map-check.coffee

@@ -0,0 +1,106 @@
+assert = require 'assert'
+fs = require 'fs'
+path = require 'path'
+
+coffee = require './lib/coffeescript/coffeescript.js'
+ts = require 'typescript'
+
+coffeeCompileWithSourceMap = (fileNames) ->
+  for f in fileNames
+    assert f.endsWith '.coffee'
+    out = f.replace /\.coffee$/, '.js'
+    mapOut = "#{out}.map"
+    code = fs.readFileSync f, 'utf8'
+    {js, v3SourceMap, sourceMap} = coffee.compile code,
+      filename: f
+      generatedFile: out
+      bare: yes
+      header: no
+      sourceMap: yes
+      sourceRoot: process.cwd()
+    fs.writeFileSync out, "#{js}\n//# sourceMappingURL=#{mapOut}\n"
+    fs.writeFileSync mapOut, "#{v3SourceMap}\n"
+    {
+      original: f
+      opath: path.resolve f
+      code: code
+      codeLines: code.split '\n'
+      js: out
+      mapFile: mapOut
+      map: sourceMap
+    }
+
+compiled = coffeeCompileWithSourceMap process.argv[2..]
+byJsPath = {}
+for {js, original, opath, code, codeLines, map} in compiled
+  byJsPath[path.resolve js] = {original, opath, code, codeLines, map}
+
+generateMappedCoffeeSource = (name, filePath, content) ->
+  {
+    ...(ts.createSourceFile name, content, ts.ScriptTarget.Latest, no, ts.ScriptKind.Unknown),
+    statements: [],
+    parseDiagnostics: [],
+    identifiers: new Map,
+    path: filePath,
+    resolvedPath: filePath,
+    originalFileName: name
+  }
+
+locationToOffset = (contentLines, line, column) ->
+  offset = 0
+  for i in [0...line]
+    cur = contentLines[i]
+    # NB: add 1 for newline
+    offset += cur.length + 1
+  offset += column
+  offset
+
+mapSpan = (diag, map, contentLines, content) ->
+  {line: startLine, character: startCol} = ts.getLineAndCharacterOfPosition diag.file, diag.start
+  {line: endLine, character: endCol} = ts.getLineAndCharacterOfPosition diag.file, (diag.start + diag.length)
+
+  [origStartLine, origStartCol] = map.sourceLocation [startLine, startCol]
+  [origEndLine, origEndCol] = map.sourceLocation [endLine, endCol]
+
+  lengthInferred = origEndLine == origStartLine and origEndCol == 0
+
+  origStart = locationToOffset contentLines, origStartLine, origStartCol
+
+  origEnd = if lengthInferred then origStart + diag.length
+  else locationToOffset contentLines, origEndLine, origEndCol
+
+  {start: origStart, length: origEnd - origStart}
+
+checkMappedJsDoc = (mappedCompiled, options) ->
+  fileNames = (k for own k of mappedCompiled)
+  for f in fileNames
+    assert f.endsWith '.js'
+  program = ts.createProgram fileNames, options
+  emitResult = program.emit()
+
+  rawDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics)
+
+  mappedDiagnostics = for diag in rawDiagnostics
+    if not diag.file? then diag else
+      {original, opath, code, codeLines, map} = mappedCompiled[diag.file.resolvedPath]
+      realSource = generateMappedCoffeeSource original, opath, code
+      {start: realStart, length: realLength} = mapSpan diag, map, codeLines, code
+      {
+        ...diag,
+        file: realSource,
+        start: realStart,
+        length: realLength,
+      }
+
+  console.log ts.formatDiagnosticsWithColorAndContext mappedDiagnostics,
+    getCurrentDirectory: -> process.cwd()
+    getNewLine: -> '\n'
+    getCanonicalFileName: (fileName) -> fileName
+
+  exitCode = if emitResult.emitSkipped then 1 else 0
+  process.exit exitCode
+
+checkMappedJsDoc byJsPath,
+  allowJs: yes
+  checkJs: yes
+  noEmit: yes

typecheck-example.coffee

@@ -0,0 +1,8 @@
+###*
+ * @type {(x: number) => number}
+###
+f = (x) -> x
+
+f("asdf")
+
+x = 3