Why tsc compiles export default xyz to xyz.default?

[zikaari]

TypeScript Version: 2.4.0 / nightly (2.5.0-dev.201xxxxx)

Code

Given foo.ts

function foo() { }
export default foo;

transpiles to foo.js as

function foo() { }
exports.default = foo

Why is that? Since consumers of my lib are used to

import foo from 'foo'
foo()

But now they need to

import foo from 'foo'
foo.default()

Expected behavior:
Shouldn't it transpile to

function foo() { }
exports = foo

Similar to what we see around most libs.

[MrKou47]

It's typescript design. Same issue TypeStrong/ts-loader#583

[zikaari]

Some background would be appreciated like what was TS team thinking when they designed this?
As this feels like going against a well known pattern/convention.

[RyanCavanaugh]

You have a default export and a default import here. If that's not working (foo() rather than foo.default()), then some other tool in your build/run pipeline is broken. TypeScript definitely emits the correct code for this.

[zikaari]

Thanks I figured it out, the issue started out of bad d.ts file.