Core: Use named exports in `src/`

The `default` export is treated differently across tooling when transpiled
to CommonJS - tools differ on whether `module.exports` represents the full
module object or just its default export. Switch `src/` modules to named
exports for tooling consistency.

Fixes gh-5262
Closes gh-5292

1 files changed, 2 insertions, 2 deletions

diff --git a/src/var/flat.js b/src/var/flat.js
index de911aeef..269ebec11 100644
--- a/src/var/flat.js
+++ b/src/var/flat.js
@@ -1,8 +1,8 @@
-import arr from "./arr.js";
+import { arr } from "./arr.js";
 
 // Support: IE 11+
 // IE doesn't have Array#flat; provide a fallback.
-export default arr.flat ? function( array ) {
+export var flat = arr.flat ? function( array ) {
 	return arr.flat.call( array );
 } : function( array ) {
 	return arr.concat.apply( [], array );