WIP: ESM support

.eslintignore

@@ -1,3 +1,4 @@
 !/.eslint.js
 /test/**/*.js
 !/test/index.js
+*.mjs

.eslintrc.json

@@ -2,6 +2,9 @@
   "root": true,
   "extends": ["./node_modules/sanctuary-style/eslint-es3.json"],
   "env": {"node": true},
+  "globals": {
+    "Promise": "readonly"
+  },
   "overrides": [
     {
       "files": ["lib/doctest.js"],

README.md

@@ -50,12 +50,13 @@ The exit code is 0 if all tests pass, 1 otherwise.
 
 doctest supports CommonJS modules and partially supports AMD modules:
 
-| Module system               | Node.js |
-| --------------------------- |:-------:|
-| AMD                         |    ✔︎    |
-| AMD w/ dependencies         |    ✘    |
-| CommonJS                    |    ✔︎    |
-| CommonJS w/ dependencies    |    ✔︎    |
+| Module system               | Option     | Node.js |
+| --------------------------- | ---------- |:-------:|
+| AMD                         | `amd`      |    ✔︎    |
+| AMD w/ dependencies         | `amd`      |    ✘    |
+| CommonJS                    | `commonjs` |    ✔︎    |
+| CommonJS w/ dependencies    | `commonjs` |    ✔︎    |
+| EcmaScript modules          | `esm`      |    ✔︎    |
 
 Specify module system via JavaScript API:
 

bin/doctest

@@ -1,15 +1,22 @@
 #!/usr/bin/env node
 
-// Based on:
-// https://github.com/jashkenas/coffeescript/blob/1.9.1/src/command.coffee#L431-L441
-var args = process.argv.slice(1);
+var path = require('path');
+
+var args = process.argv.slice(2);
 var idx = args.indexOf('--nodejs');
-if (idx < 0 || idx === args.length - 1) {
-  require('../lib/command');
-} else {
-  require('child_process').spawn(
-    process.execPath,
-    args[idx + 1].split(/\s+/).concat(args.slice(0, idx), args.slice(idx + 2)),
-    {cwd: process.cwd(), env: process.env, stdio: [0, 1, 2]}
-  ).on('exit', process.exit);
-}
+var esm = Number(process.versions.node.split('.')[0]) >= 9;
+var flags = idx >= 0 && idx < args.length - 1;
+
+var nodeargs = []
+  .concat(flags ? args[idx + 1].split(/\s+/) : [])
+  .concat(esm ? '--experimental-modules' : []);
+
+var script = path.resolve(__dirname, '../lib/command');
+
+var scriptargs = flags ? args.slice(0, idx).concat(args.slice(idx + 2)) : args;
+
+require('child_process').spawn(
+  process.execPath,
+  nodeargs.concat([script]).concat(scriptargs),
+  {cwd: process.cwd(), env: process.env, stdio: [0, 1, 2]}
+).on('exit', process.exit);

lib/command.js

@@ -1,38 +1,14 @@
 'use strict';
 
-var program = require ('commander');
-
+var common = require ('./common');
+var program = require ('./program');
 var doctest = require ('..');
-var pkg = require ('../package.json');
-
-
-program
-.version (pkg.version)
-.usage ('[options] path/to/js/or/coffee/module')
-.option ('-m, --module <type>',
-         'specify module system ("amd" or "commonjs")')
-.option ('    --nodejs <options>',
-         'pass options directly to the "node" binary')
-.option ('    --prefix <prefix>',
-         'specify Transcribe-style prefix (e.g. ".")')
-.option ('    --opening-delimiter <delimiter>',
-         'specify line preceding doctest block (e.g. "```javascript")')
-.option ('    --closing-delimiter <delimiter>',
-         'specify line following doctest block (e.g. "```")')
-.option ('-p, --print',
-         'output the rewritten source without running tests')
-.option ('-s, --silent',
-         'suppress output')
-.option ('-t, --type <type>',
-         'specify file type ("coffee" or "js")')
-.parse (process.argv);
 
-//  formatErrors :: Array String -> String
-function formatErrors(errors) {
-  return (errors.map (function(s) { return 'error: ' + s + '\n'; })).join ('');
-}
 
 var errors = [];
+if (program.module === 'esm' || program.type === 'esm') {
+  errors.push ('EcmaScript modules only supported in Node version 9 and up');
+}
 if (program.module != null &&
     program.module !== 'amd' &&
     program.module !== 'commonjs') {
@@ -44,19 +20,21 @@ if (program.type != null &&
   errors.push ('Invalid type `' + program.type + "'");
 }
 if (errors.length > 0) {
-  process.stderr.write (formatErrors (errors));
+  process.stderr.write (common.formatErrors (errors));
   process.exit (1);
 }
 
-process.exit (program.args.reduce (function(status, path) {
-  var results;
-  try {
-    results = doctest (path, program);
-  } catch (err) {
-    process.stderr.write (formatErrors ([err.message]));
-    process.exit (1);
-  }
-  return results.reduce (function(status, tuple) {
-    return tuple[0] ? status : 1;
-  }, status);
-}, 0));
+Promise.all (program.args.map (function(path) {
+  return doctest (path, program).then (function(results) {
+    return results.reduce (function(status, tuple) {
+      // Note: This will cause a non-zero-exit to go back to zero.
+      // I think it's a bug, but it was already there.
+      return tuple[0] ? status : 1;
+    }, 0);
+  });
+})).then (function(statuses) {
+  process.exit (Math.max.apply (null, statuses));
+}, function(err) {
+  process.stderr.write (common.formatErrors ([err.message]));
+  process.exit (1);
+});

lib/command.mjs

@@ -0,0 +1,20 @@
+import common from './common';
+import program from './program';
+import doctest from '..';
+
+Promise.all (program.args.map (function(path) {
+  return doctest (path, program).then (function(results) {
+    console.log (path, results);
+    return results.reduce (function(status, tuple) {
+      // Note: This will cause a non-zero-exit to go back to zero.
+      // I think it's a bug, but it was already there.
+      return tuple[0] ? status : 1;
+    }, 0);
+  });
+})).then (function(statuses) {
+  process.exit (Math.max.apply (null, statuses));
+}, function(err) {
+  console.error (err.stack); //TMP
+  process.stderr.write (common.formatErrors ([err.message]));
+  process.exit (1);
+});

lib/common.js

@@ -0,0 +1,17 @@
+'use strict';
+
+
+//  formatErrors :: Array String -> String
+exports.formatErrors = function(errors) {
+  return (errors.map (function(s) { return 'error: ' + s + '\n'; })).join ('');
+};
+
+//  sanitizeFileContents :: String -> String
+exports.sanitizeFileContents = function(contents) {
+  return contents.replace (/\r\n?/g, '\n').replace (/^#!.*/, '');
+};
+
+//  unlines :: Array String -> String
+exports.unlines = function(lines) {
+  return lines.reduce (function(s, line) { return s + line + '\n'; }, '');
+};

lib/doctest.js

@@ -18,6 +18,7 @@ var esprima = require ('esprima');
 var _show = require ('sanctuary-show');
 var Z = require ('sanctuary-type-classes');
 
+var common = require ('./common');
 
 function inferType(path) {
   switch (pathlib.extname (path)) {
@@ -52,23 +53,21 @@ module.exports = function(path, options) {
       {prefix: options.prefix == null ? '' : options.prefix,
        openingDelimiter: options.openingDelimiter,
        closingDelimiter: options.closingDelimiter},
-      fs.readFileSync (path, 'utf8')
-        .replace (/\r\n?/g, '\n')
-        .replace (/^#!.*/, '')
+      common.sanitizeFileContents (fs.readFileSync (path, 'utf8'))
     ),
     options.module
   );
 
   if (options.print) {
     console.log (source.replace (/\n$/, ''));
-    return [];
+    return Promise.resolve ([]);
   } else if (options.silent) {
-    return evaluate (options.module, source, path);
+    return Promise.resolve (evaluate (options.module, source, path));
   } else {
     console.log ('running doctests in ' + path + '...');
     var results = evaluate (options.module, source, path);
     log (results);
-    return results;
+    return Promise.resolve (results);
   }
 };
 
@@ -111,11 +110,6 @@ function stripLeading(n, c, s) {
   return s.slice (idx);
 }
 
-//  unlines :: Array String -> String
-function unlines(lines) {
-  return lines.reduce (function(s, line) { return s + line + '\n'; }, '');
-}
-
 //  iifeWrap :: String -> String
 function iifeWrap(s) {
   return 'void function() {\n' + indentN (2, s) + '}.call(this);';
@@ -125,7 +119,7 @@ function iifeWrap(s) {
 function toModule(source, moduleType) {
   switch (moduleType) {
     case 'amd':
-      return unlines ([
+      return common.unlines ([
         source,
         'function define() {',
         '  for (var idx = 0; idx < arguments.length; idx += 1) {',
@@ -137,7 +131,7 @@ function toModule(source, moduleType) {
         '}'
       ]);
     case 'commonjs':
-      return iifeWrap (unlines ([
+      return iifeWrap (common.unlines ([
         'var __doctest = {',
         '  require: require,',
         '  queue: [],',
@@ -378,7 +372,11 @@ function rewrite$js(options, input) {
   //     produced by step 6 (substituting "step 6" for "step 2").
 
   function getComments(input) {
-    return (esprima.parse (input, {comment: true, loc: true})).comments;
+    return (esprima.parse (input, {
+      comment: true,
+      loc: true,
+      sourceType: options.sourceType || 'script'
+    })).comments;
   }
 
   //  comments :: { Block :: Array Comment, Line :: Array Comment }
@@ -423,6 +421,8 @@ function rewrite$js(options, input) {
     .join ('');
 }
 
+module.exports.rewrite$js = rewrite$js;
+
 function rewrite$coffee(options, input) {
   var lines = input.match (/^.*(?=\n)/gm);
   var chunks = lines.reduce (function(accum, line, idx) {
@@ -548,6 +548,8 @@ function run(queue) {
   }, {results: [], thunk: null}).results;
 }
 
+module.exports.run = run;
+
 function log(results) {
   console.log (results.reduce (function(s, tuple) {
     return s + (tuple[0] ? '.' : 'x');
@@ -559,3 +561,5 @@ function log(results) {
     }
   });
 }
+
+module.exports.log = log;

lib/doctest.mjs

@@ -0,0 +1,67 @@
+import {readFile, writeFile, unlink} from 'fs';
+import {resolve} from 'path';
+import {promisify} from 'util';
+
+import common from './common';
+import doctest from './doctest.js';
+
+export default async function(path, options) {
+  if (options.module === 'esm') {
+    if (options.type && options.type !== 'esm') {
+      throw new Error (
+        'EcmaScript modules only work with the EcmaScript module type'
+      );
+    }
+  } else {
+    return doctest (path, options);
+  }
+
+  const source = wrap (
+    doctest.rewrite$js (
+      {prefix: options.prefix == null ? '' : options.prefix,
+       openingDelimiter: options.openingDelimiter,
+       closingDelimiter: options.closingDelimiter,
+       sourceType: 'module'},
+      common.sanitizeFileContents (
+        await promisify (readFile) (path, 'utf8')
+      )
+    )
+  );
+
+  if (options.print) {
+    console.log (source.replace (/\n$/, ''));
+    return [];
+  } else if (options.silent) {
+    return evaluate (source, path);
+  } else {
+    console.log ('running doctests in ' + path + '...');
+    return (evaluate (source, path)).then(function(results) {
+      doctest.log (results);
+      return results;
+    });
+  }
+}
+
+function wrap(source) {
+  return common.unlines ([
+    'export const __doctest = {',
+    '  queue: [],',
+    '  enqueue: function(io) { this.queue.push(io); }',
+    '};',
+    '',
+    source,
+  ]);
+}
+
+function evaluate(source, path) {
+  const abspath =
+  (resolve (path)).replace (/[.][^.]+$/, '-' + Date.now () + '.mjs');
+
+  return promisify (writeFile) (abspath, source).then(function() {
+    return import (abspath);
+  }).then (function(module) {
+    return doctest.run (module.__doctest.queue);
+  }).finally (function() {
+    return promisify (unlink) (abspath);
+  });
+}

lib/program.js

@@ -0,0 +1,29 @@
+'use strict';
+
+var program = require ('commander');
+
+var pkg = require ('../package.json');
+
+
+program
+.version (pkg.version)
+.usage ('[options] path/to/js/or/coffee/module')
+.option ('-m, --module <type>',
+         'specify module system ("amd", "commonjs", or "esm")')
+.option ('    --nodejs <options>',
+         'pass options directly to the "node" binary')
+.option ('    --prefix <prefix>',
+         'specify Transcribe-style prefix (e.g. ".")')
+.option ('    --opening-delimiter <delimiter>',
+         'specify line preceding doctest block (e.g. "```javascript")')
+.option ('    --closing-delimiter <delimiter>',
+         'specify line following doctest block (e.g. "```")')
+.option ('-p, --print',
+         'output the rewritten source without running tests')
+.option ('-s, --silent',
+         'suppress output')
+.option ('-t, --type <type>',
+         'specify file type ("coffee", "js", or "esm")')
+.parse (process.argv);
+
+module.exports = program;