Add --no-esm flag to disable '-r esm' behavior

Re #517
Re #516

Author: isaacs

bin/run.js

@@ -124,13 +124,14 @@ const constructDefaultArgs = _ => {
   const defaultTimeout = global.__coverage__ ? 240 : 30
 
   const defaultArgs = {
-    nodeArgs: [ '-r', require.resolve('esm') ],
+    nodeArgs: [],
     nycArgs: [],
     testArgs: [],
     timeout: +process.env.TAP_TIMEOUT || defaultTimeout,
     color: !!colorSupport.level,
     reporter: null,
     files: [],
+    esm: true,
     grep: [],
     grepInvert: false,
     bail: false,
@@ -262,6 +263,14 @@ const parseArgs = (args, options) => {
         defaultCoverage = true
         continue
 
+      case '--no-esm':
+        options.esm = false
+        continue
+
+      case '--esm':
+        options.esm = true
+        continue
+
       case '--no-browser':
         options.browser = false
         continue
@@ -706,6 +715,7 @@ const runAllFiles = (options, saved, tap) => {
 
   options.files = filterFiles(options.files, saved, parallelOk)
   let tapChildId = 0
+  const esmArg = options.esm ? ['-r', require.resolve('esm')] : []
 
   for (let i = 0; i < options.files.length; i++) {
     const opt = {}
@@ -738,10 +748,10 @@ const runAllFiles = (options, saved, tap) => {
         opt.buffered = isParallelOk(parallelOk, file) !== false
 
       if (file.match(/\.m?js$/)) {
-        const args = options.nodeArgs.concat(file).concat(options.testArgs)
+        const args = esmArg.concat(options.nodeArgs).concat(file).concat(options.testArgs)
         tap.spawn(node, args, opt, file)
       } else if (file.match(/\.ts$/)) {
-        const args = options.nodeArgs.concat(file).concat(options.testArgs)
+        const args = esmArg.concat(options.nodeArgs).concat(file).concat(options.testArgs)
         tap.spawn(tsNode, args, opt, file)
       } else if (isexe.sync(options.files[i]))
         tap.spawn(options.files[i], options.testArgs, opt, file)

bin/usage.txt

@@ -17,6 +17,11 @@ Coverage is never enabled for stdin.
 
 Options:
 
+  --esm                       Support ES Modules in *.js and *.mjs files.
+                              (Default)
+
+  --no-esm                    Do not add support for ES Modules.
+
   -j<n> --jobs=<n>            Run up to <n> test files in parallel
                               Note that this causes tests to be run in
                               "buffered" mode, so line-by-line results

docs/cli/index.md

@@ -27,6 +27,11 @@ Coverage is never enabled for stdin.
 
 Options:
 
+  --esm                       Support ES Modules in *.js and *.mjs files.
+                              (Default)
+
+  --no-esm                    Do not add support for ES Modules.
+
   -j<n> --jobs=<n>            Run up to <n> test files in parallel
                               Note that this causes tests to be run in
                               "buffered" mode, so line-by-line results

package.json

@@ -60,8 +60,8 @@
   "repository": "https://github.com/tapjs/node-tap.git",
   "scripts": {
     "regen-fixtures": "node scripts/generate-test-test.js test-legacy/test/*.js",
-    "snap": "TAP_SNAPSHOT=1 node bin/run.js test/*.js -J",
-    "test": "node bin/run.js test/*.js --100 -J --nyc-arg=--include={lib,bin} -c",
+    "snap": "TAP_SNAPSHOT=1 node bin/run.js --no-esm test/*.js -J",
+    "test": "node bin/run.js --no-esm test/*.js --100 -J --nyc-arg=--include={lib,bin} -c",
     "test-all": "node bin/run.js test/*.js test-legacy/*.js --100 -J --nyc-arg=--include={lib,bin} && npm run test-browser",
     "test-browser": "node browser-test.js",
     "unit": "bash scripts/unit.sh",

test/run.js

@@ -133,8 +133,7 @@ t.test('dump config stuff', t => {
       t.equal(er, null)
       t.match(JSON.parse(o), {
         nodeArgs:
-         [ '-r', 'esm',
-           '--expose-gc',
+         [ '--expose-gc',
            '--use_strict',
            '--debug',
            '--debug-brk',
@@ -642,7 +641,7 @@ t.test('mjs', t => {
     import t from ${tap}
     t.pass('this is fine')
   `)
-  run([ok], {}, (er, o, e) => {
+  run([ok, '--esm'], {}, (er, o, e) => {
     t.equal(er, null)
     t.matchSnapshot(clean(o))
     t.end()
@@ -654,7 +653,7 @@ t.test('esm', t => {
     import {t} from ${tap}
     t.pass('this is fine')
   `)
-  run([ok], {}, (er, o, e) => {
+  run([ok, '--esm'], {}, (er, o, e) => {
     t.equal(er, null)
     t.matchSnapshot(clean(o))
     t.end()
@@ -666,7 +665,7 @@ t.test('ts', t => {
     import * as t from ${tap}
     t.pass('this is fine')
   `)
-  run([ok], {}, (er, o, e) => {
+  run([ok, '--esm'], {}, (er, o, e) => {
     t.equal(er, null)
     t.matchSnapshot(clean(o))
     t.end()