This repo contains a repro case for a possible bug in Babel involving babel-plugin-transform-es2015-destructuring, babel-plugin-transform-es2015-modules-commonjs, and babel-plugin-transform-es3-property-literals.

The es3-property-literals plugin normally converts keys that are like default to be quoted, which provides better compatibility for browsers that do not support ES5 (e.g. IE8). This seems to work when the source code contains the property that needs to be quoted, but when used in conjunction with these other two plugins in some situations the property is not quoted.

In src/okay.js we have the following code:

import foo from 'foo';
const bar = [1, 2, 3];
const [x] = bar;

Part of which gets transpiled to the following line in build/okay.js:

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

In src/bad.js we have the following code:

import foo from 'foo';
const [x] = bar;

Part of which gets transpiled to the following line in build/bad.js (note the missing quotes around default:

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }