Improper ES6 import statement breaks (so far unnoticed because of correct CJS result)

[sarimarton]

Code to reproduce the issue:

index.js:

import { run } from '@cycle/run'
import { timeDriver } from '@cycle/time'

function main (sources) {
  return {}
}

const drivers = {
  Time: timeDriver
}

run(main, drivers)

index.html:

<script src="index.js"></script>

package.json:

{
  "main": "index.html",
  "scripts": {
    "start": "parcel index.html"
  },
  "devDependencies": {
    "@babel/core": "^7.5.5",
    "parcel": "^1.12.3"
  },
  "dependencies": {
    "@cycle/run": "^5.2.0",
    "@cycle/time": "^0.19.0"
  }
}

Open http://localhost:1234/ in the browser.

Expected behavior:

Nothing happens, empty screen, no log message.

Actual behavior:

JS error thrown: Uncaught TypeError: requestAnimationFrame is not a function

Versions of packages used:

See above in package.json

I provided a fix at #891

The problem is this 2 lines in @cycle/time/lib/es6/src/time-driver.js:

// WRONG
import * as requestAnimationFrame from 'raf';
import * as now from 'performance-now';

Those 2 modules export functions, not namespace objects. import * always creates a plain namespace object, which can't be invoked. The correct import statement is without the wildcard:

// WORKS OK
import requestAnimationFrame from 'raf';
import now from 'performance-now';

This bug was unnoticed so far, because most bundler setups are pulling the cjs version (@cycle/time/lib/cjs/src/time-driver.js) instead of the es6 one, and both types of import statements produces the same var <f> = require('...') statement in cjs, which works, because it pulls in the module.exports object - in these cases the function itself.

The es6 version is broken however, and with bundlers which use the es6 version, the result bundle will break.

[sarimarton]

Currenlty a workaround for the problem is to force loading the cjs version:
import { timeDriver } from '@cycle/time/lib/cjs'

[sarimarton]

Bump.

Hello guys, this is actually an easy fix, and a pretty basic bug... Can someone please take a look?

Here is an online repro: https://codesandbox.io/s/cycletime-improper-import-statement-kgd02

I don't know about the CI builds and tests (I tried, but they were not up-to-date, I see there's some work on it nowadays), but I know that the fix doesn't change the cjs result, so no tests should be impacted.