1 files changed, 79 insertions, 0 deletions
diff --git a/date-fns/scripts/build/_lib/addDenoExtensions.ts b/date-fns/scripts/build/_lib/addDenoExtensions.ts
new file mode 100644
index 0000000..f0e43d6
--- /dev/null
+++ b/date-fns/scripts/build/_lib/addDenoExtensions.ts
@@ -0,0 +1,79 @@
+import { resolve, dirname } from 'path'
+import fs from 'fs'
+import globby from 'globby'
+import ts, {
+  ExportDeclaration,
+  ImportDeclaration,
+  StringLiteral,
+} from 'typescript'
+
+const { readFile, writeFile, stat } = fs.promises
+
+const pattern = /\.(ts|js)$/
+const ignore = [/\.d\.ts$/]
+
+const resolvedExtensions: Record<string, string> = {}
+
+globby('deno')
+  .then((files) =>
+    files.filter(
+      (file) => pattern.test(file) && !ignore.find((p) => p.test(file))
+    )
+  )
+  .then((files) =>
+    Promise.all(
+      files.map((file) =>
+        readFile(file, 'utf8').then(async (content) => {
+          const source = ts.createSourceFile(
+            file,
+            content,
+            ts.ScriptTarget.Latest
+          )
+          const imports: string[] = []
+
+          source.forEachChild((node) => {
+            if (
+              [
+                ts.SyntaxKind.ImportDeclaration,
+                ts.SyntaxKind.ExportDeclaration,
+              ].includes(node.kind)
+            ) {
+              const importNode = node as ImportDeclaration | ExportDeclaration
+              const specifier = importNode.moduleSpecifier as StringLiteral
+              const importPath = specifier.text
+              const isLocal = /\.\/.+/
+              if (isLocal) imports.push(importPath)
+            }
+          })
+
+          await Promise.all(
+            imports.map(async (importPath) => {
+              if (resolvedExtensions[importPath]) return
+              const fullPath = resolveFullPath(file, importPath)
+              let isTs = false
+              try {
+                await stat(fullPath + '.ts')
+                isTs = true
+              } catch (_) {}
+              resolvedExtensions[fullPath] = isTs ? '.ts' : '.js'
+            })
+          )
+
+          return writeFile(
+            file,
+            imports.reduce((acc, importPath) => {
+              const fullPath = resolveFullPath(file, importPath)
+              return acc.replace(
+                new RegExp(importPath, 'g'),
+                importPath + resolvedExtensions[fullPath]
+              )
+            }, content)
+          )
+        })
+      )
+    )
+  )
+
+function resolveFullPath(file: string, importPath: string) {
+  return resolve(dirname(file), importPath)
+}