codecombat / codecombat/esper.js
Cannot load core-js
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- Dominant language
- JavaScript
- Stars
- 99
- Forks
- 21
- PR merge metrics
- No merged PRs in 30d
Description
core-js is a popular ES6 polyfill:
https://github.com/zloirock/core-js
For example, it's used in Babel:
https://babeljs.io/docs/en/babel-preset-env
I've used rollup:
https://github.com/ngocdaothanh/one-core-js
To merge all ES6 polyfill files:
https://github.com/zloirock/core-js/blob/master/packages/core-js/es/index.js
Into this one file:
https://github.com/ngocdaothanh/one-core-js/blob/master/es6polyfills.js
When esper.js loads that file, there's error:
Cant index propertyIsEnumerable of undefined
The error is thrown from here:
https://github.com/codecombat/esper.js/blob/master/src/Evaluator.js#L406
Would you please investigate and fix the error?
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the failure by loading the bundled es6polyfills.js in esper.js, then inspect src/Evaluator.js at line 406 and compare it with the referenced core-js and Rollup output. Done means the bundled ES6 polyfill loads without the propertyIsEnumerable error and the relevant evaluator behavior is covered by verification.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100