Use ESM resolving algorithm

lib/generate/config.js

@@ -1,17 +1,18 @@
+import url from 'url'
+import {resolve} from 'import-meta-resolve'
 import {nanoid} from 'nanoid'
-import resolveFrom from 'resolve-from'
 import {relativeModule} from '../util/relative-module.js'
 
-export function config(ctx) {
+export async function config(ctx) {
   const options = ctx.options
   const pkg = ctx.pkg || {}
   const cwd = ctx.file.cwd
-  const mainRoot = options.main ? cwd : ctx.pkgRoot || cwd
-  const mainId = relativeModule(options.main || pkg.main || '')
+  const mainRoot = url.pathToFileURL(options.main ? cwd : ctx.pkgRoot || cwd)
+  const mainId = relativeModule(options.main || pkg.main || 'index.js')
   let main
 
   try {
-    main = resolveFrom(mainRoot, mainId)
+    main = await resolve(mainId, mainRoot.href + '/')
   } catch {}
 
   ctx.cwd = cwd

lib/generate/find-example.js

@@ -1,47 +1,52 @@
+import url from 'url'
 import {promises as fs} from 'fs'
-import resolveFrom from 'resolve-from'
+import {resolve} from 'import-meta-resolve'
 import {relativeModule} from '../util/relative-module.js'
 
 export async function findExample(ctx) {
   const fn = ctx.options.example ? findExplicitExample : findImplicitExample
-  const filePath = await fn(ctx)
+  const fileUrl = await fn(ctx)
 
-  if (!filePath) {
+  if (!fileUrl) {
     throw new Error('Could not find example')
   }
 
-  const example = String(await fs.readFile(filePath))
+  const example = String(await fs.readFile(new URL(fileUrl)))
 
-  ctx.examplePath = filePath
+  ctx.exampleFileUrl = fileUrl
   // Make sure there is a final line feed.
   ctx.example =
     example.charAt(example.length - 1) === '\n' ? example : example + '\n'
 }
 
 function findExplicitExample(ctx) {
-  const moduleId = relativeModule(ctx.options.example)
-
-  try {
-    return resolveFrom(ctx.cwd, moduleId)
-    // Catch just to be sure.
-    /* c8 ignore next */
-  } catch {}
+  return resolve(
+    relativeModule(ctx.options.example),
+    url.pathToFileURL(ctx.cwd).href + '/'
+  )
 }
 
 async function findImplicitExample(ctx) {
-  const examples = [
-    './example',
-    './examples',
-    './doc/example',
-    './docs/example'
-  ]
+  const from = url.pathToFileURL(ctx.cwd).href + '/'
+  const promises = [
+    './example.js',
+    './example/index.js',
+    './examples.js',
+    './examples/index.js',
+    './doc/example.js',
+    './doc/example/index.js',
+    './docs/example.js',
+    './docs/example/index.js'
+  ].map((d) => resolve(d, from))
+
+  const examples = await Promise.allSettled(promises)
   let index = -1
 
   while (++index < examples.length) {
-    const filePath = resolveFrom.silent(ctx.cwd, examples[index])
+    const example = examples[index]
 
-    if (filePath) {
-      return filePath
+    if (example.status === 'fulfilled') {
+      return example.value
     }
   }
 }

lib/generate/find-package.js

@@ -13,9 +13,9 @@ export async function findPackage(ctx) {
 
   try {
     await read(pkgFile)
-  } catch (error) {
     // Doesn’t consistently happen.
-    /* c8 ignore next 3 */
+    /* c8 ignore next 5 */
+  } catch (error) {
     if (error.code !== 'ENOENT') {
       throw new Error('Could not read package: ' + error)
     }

lib/generate/instrument.js

@@ -1,24 +1,42 @@
-import path from 'path'
+import {resolve} from 'import-meta-resolve'
 import babel from '@babel/core'
-import resolveFrom from 'resolve-from'
 
 export async function instrument(ctx) {
   const logs = []
   const mainReferences = []
+  const nodes = []
   let result
 
   try {
     result = await babel.transformAsync(ctx.example, {
       plugins: [addIdToConsoleLog],
       cwd: ctx.cwd,
-      filename: ctx.examplePath,
+      filename: ctx.exampleFileUrl,
       caller: {name: 'remark-usage'},
       sourceType: 'unambiguous'
     })
   } catch (error) {
     throw new Error('Could not parse example: ' + error)
   }
 
+  const promises = nodes.map((node) => {
+    return resolve(node.value, ctx.exampleFileUrl).then((resolved) => {
+      if (resolved === ctx.main) {
+        // Babel always adds raw, but just to be sure.
+        /* c8 ignore next */
+        const raw = (node && node.extra && node.extra.raw) || "'"
+
+        mainReferences.push({
+          start: node.start,
+          end: node.end,
+          quote: raw.charAt(0)
+        })
+      }
+    })
+  })
+
+  await Promise.allSettled(promises)
+
   ctx.exampleInstrumented = result.code
   ctx.logs = logs
   ctx.mainReferences = mainReferences
@@ -50,23 +68,7 @@ export async function instrument(ctx) {
     }
 
     function instrumentMainReference(node) {
-      let raw = node && node.extra && node.extra.raw
-      const filePath = resolveFrom.silent(
-        path.dirname(ctx.examplePath),
-        node.value
-      )
-
-      // Babel always adds raw, but just to be sure.
-      /* c8 ignore next */
-      if (!raw) raw = "'"
-
-      if (filePath && filePath === ctx.main) {
-        mainReferences.push({
-          start: node.start,
-          end: node.end,
-          quote: raw.charAt(0)
-        })
-      }
+      nodes.push(node)
     }
 
     function instrumentConsoleLog(path) {

lib/generate/write.js

@@ -1,10 +1,12 @@
+import url from 'url'
 import {promises as fs} from 'fs'
 import path from 'path'
 
 export async function write(ctx) {
+  const examplePath = url.fileURLToPath(ctx.exampleFileUrl)
   const filePath = path.join(
-    path.dirname(ctx.examplePath),
-    ctx.id + path.extname(ctx.examplePath)
+    path.dirname(examplePath),
+    ctx.id + path.extname(examplePath)
   )
 
   await fs.writeFile(filePath, ctx.exampleInstrumented)

package.json

@@ -34,10 +34,10 @@
   ],
   "dependencies": {
     "@babel/core": "^7.0.0",
+    "import-meta-resolve": "^1.0.0",
     "mdast-util-heading-range": "^3.0.0",
     "nanoid": "^3.0.0",
     "remark-parse": "^10.0.0",
-    "resolve-from": "^5.0.0",
     "to-vfile": "^7.0.0",
     "trough": "^2.0.0",
     "unified": "^10.0.0",

test/fixtures/normal-custom-example/config.json

@@ -1,3 +1,3 @@
 {
-  "example": "./ex"
+  "example": "./ex.js"
 }

test/fixtures/normal-custom-name-without-package/example.js

@@ -1,5 +1,5 @@
 // Require `pi`:
-var pi = require('.')
+var pi = require('./index.js')
 
 // Logs:
 console.log('text', pi)