tl;dr: baz() { this.foo(); this.bar() }
In ES2015 this construct:
var obj = {
foo() { console.log('foo') }
}
is equal to this ES5 code:
var obj = {
foo : function foo() { console.log('foo') }
}
exports.default = {} is like creating an object, your default export translates to ES5 code like this:
exports['default'] = {
foo: function foo() {
console.log('foo');
},
bar: function bar() {
console.log('bar');
},
baz: function baz() {
foo();bar();
}
};
now it's kind of obvious (I hope) that baz tries to call foo and bar defined somewhere in the outer scope, which are undefined. But this.foo and this.bar will resolve to the keys defined in exports['default'] object. So the default export referencing its own methods shold look like this:
export default {
foo() { console.log('foo') },
bar() { console.log('bar') },
baz() { this.foo(); this.bar() }
}