Add support for importing dependencies in esm examples

README.md

@@ -54,7 +54,7 @@ doctest supports the following module systems:
 | ------------------ | ---------- |:-------:|:------------:|
 | AMD                | `amd`      |    ✔︎    |       ✘      |
 | CommonJS           | `commonjs` |    ✔︎    |       ✔︎      |
-| EcmaScript modules | `esm`      |    ✔︎    |       ✔︎      |
+| ECMAScript modules | `esm`      |    ✔︎    |       ✔︎      |
 
 Specify module system via JavaScript API:
 

bin/doctest

@@ -9,18 +9,12 @@ var idx = args.indexOf ('--nodejs');
 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),
+  [].concat (esm ? ['--experimental-modules'] : [])
+    .concat (flags ? args[idx + 1].split (/\s+/) : [])
+    .concat ([path.resolve (__dirname, '..', 'lib', 'command')])
+    .concat (flags ? (args.slice (0, idx)).concat (args.slice (idx + 2))
+                   : args),
   {cwd: process.cwd (), env: process.env, stdio: [0, 1, 2]}
 ).on ('exit', process.exit);

lib/command.js

@@ -8,7 +8,7 @@ var doctest = require ('..');
 if (program.module === 'esm' || program.type === 'esm') {
   process.stderr.write (
     common.formatErrors (
-      ['EcmaScript modules only supported in Node version 9 and up']
+      ['ECMAScript modules only supported in Node version 9 and up']
     )
   );
   process.exit (1);

lib/doctest.js

@@ -314,9 +314,12 @@ function substring(input, start, end) {
   );
 }
 
-function wrap$js(test) {
-  var type = (esprima.parse (test[INPUT].value)).body[0].type;
-  return type === 'FunctionDeclaration' || type === 'VariableDeclaration' ?
+function wrap$js(test, sourceType) {
+  var ast = esprima.parse (test[INPUT].value, {sourceType: sourceType});
+  var type = ast.body[0].type;
+  return type === 'FunctionDeclaration' ||
+         type === 'ImportDeclaration' ||
+         type === 'VariableDeclaration' ?
     test[INPUT].value :
     [
       '__doctest.enqueue({',
@@ -384,11 +387,16 @@ function rewrite$js(options, input) {
   //     produced by step 6 (substituting "step 6" for "step 2").
 
   function getComments(input) {
-    return (esprima.parse (input, {
+    var ast = esprima.parse (input, {
       comment: true,
       loc: true,
       sourceType: options.sourceType
-    })).comments;
+    });
+    return ast.comments;
+  }
+
+  function wrapCode(js) {
+    return wrap$js (js, options.sourceType);
   }
 
   //  comments :: { Block :: Array Comment, Line :: Array Comment }
@@ -411,7 +419,7 @@ function rewrite$js(options, input) {
 
   //  source :: String
   var source = lineTests
-    .map (wrap$js)
+    .map (wrapCode)
     .concat ([''])
     .reduce (function(accum, s, idx) { return accum + chunks[idx] + s; }, '');
 
@@ -423,7 +431,7 @@ function rewrite$js(options, input) {
         substring (source, accum.loc, comment.loc.start),
         blockTests
           .filter (function(test) { return test.commentIndex === idx; })
-          .map (wrap$js)
+          .map (wrapCode)
           .join ('\n')
       );
       accum.loc = comment.loc.end;

lib/doctest.mjs

@@ -5,12 +5,11 @@ 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 != null && options.type !== 'esm') {
-      throw new Error (
-        'EcmaScript modules only work with the EcmaScript module type'
-      );
+    if (options.type != null) {
+      throw new Error ('Cannot use file type when module is "esm"');
     }
   } else {
     return doctest (path, options);
@@ -57,11 +56,8 @@ 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);
-  });
+  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

@@ -23,7 +23,7 @@ program
 .option ('-s, --silent',
          'suppress output')
 .option ('-t, --type <type>',
-         'specify file type ("coffee", "js", or "esm")')
+         'specify file type for non-esm module systems ("coffee" or "js")')
 .parse (process.argv);
 
 module.exports = program;

test/esm/dependencies.mjs

@@ -0,0 +1,8 @@
+// Convert degrees Celsius to degrees Fahrenheit.
+//
+// > import {inspect} from 'util'
+// > inspect (toFahrenheit (0))
+// '32'
+export function toFahrenheit(degreesCelsius) {
+  return degreesCelsius * 9 / 5 + 32;
+}

test/index.js

@@ -221,6 +221,15 @@ if (esmSupported) {
     stderr: ''
   });
 
+  testCommand ('bin/doctest --module esm test/esm/dependencies.mjs', {
+    status: 0,
+    stdout: unlines ([
+      'running doctests in test/esm/dependencies.mjs...',
+      '.'
+    ]),
+    stderr: ''
+  });
+
   testCommand ('bin/doctest --module esm test/esm/incorrect.mjs', {
     status: 1,
     stdout: unlines ([