[
https://issues.apache.org/jira/browse/ARROW-12636?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Howard Zuo updated ARROW-12636:
-------------------------------
Description:
When a JS application depends on `apache-arrow` or any of the ESM variants,
Arrow's package.json declares `sideEffects: false` which allows bundlers like
Webpack or Rollup to remove all code that's evaluated at the top level of all
modules (tree shaking ~= any code that isn't explicitly imported can be pruned).
However, there are important top-level side effects that arrow relies on, e.g.
for binding methods on types:
[https://github.com/apache/arrow/blob/c0445d69088a6fbd9c026ecac6a99c6cd4df4865/js/src/vector/index.ts#L167-L179]
So currently, any JS app that uses tree-shaking and depends on `apache-arrow`
or the ESM variants will throw if any of those methods are called, e.g. in my
case I see `TypeError: e._chunks[t].get is not a function` when calling
`table.get`.
Indeed switching to the CJS variants like `@apache-arrow/es2015-cjs` fixes the
issue, since the Arrow build does not inject `sideEffects: false` into its
package.json for non-ESM variants.
For reference, the `sideEffects: false` logic was introduced in this PR and
issue:
[https://github.com/apache/arrow/pull/8418/]
https://issues.apache.org/jira/browse/ARROW-10255
was:
When a JS application depends on `apache-arrow` or any of the ESM variants,
Arrow's package.json declares `sideEffects: false` which allows bundlers like
Webpack or Rollup to remove all code that's evaluated at the top level of all
modules (tree shaking ~= any code that isn't explicitly imported can be pruned).
However, there are important top-level side effects that arrow relies on, e.g.
for binding methods on types:
[https://github.com/apache/arrow/blob/c0445d69088a6fbd9c026ecac6a99c6cd4df4865/js/src/vector/index.ts#L167-L179]
So currently, any JS app that uses tree-shaking and depends on `apache-arrow`
or the ESM variants will throw if any of those methods are called, e.g. in my
case I see `TypeError: e._chunks[t].get is not a function` when calling
`table.get`.
Indeed switching to the CJS variants like `@apache-arrow/es2015-cjs` fixes the
issue.
For reference, the `sideEffects: false` logic was introduced in this PR and
issue:
[https://github.com/apache/arrow/pull/8418/]
https://issues.apache.org/jira/browse/ARROW-10255
> [JS] ESM Tree-Shaking produces broken code
> ------------------------------------------
>
> Key: ARROW-12636
> URL: https://issues.apache.org/jira/browse/ARROW-12636
> Project: Apache Arrow
> Issue Type: Bug
> Components: JavaScript
> Affects Versions: 4.0.0
> Reporter: Howard Zuo
> Priority: Major
>
> When a JS application depends on `apache-arrow` or any of the ESM variants,
> Arrow's package.json declares `sideEffects: false` which allows bundlers like
> Webpack or Rollup to remove all code that's evaluated at the top level of all
> modules (tree shaking ~= any code that isn't explicitly imported can be
> pruned).
>
> However, there are important top-level side effects that arrow relies on,
> e.g. for binding methods on types:
> [https://github.com/apache/arrow/blob/c0445d69088a6fbd9c026ecac6a99c6cd4df4865/js/src/vector/index.ts#L167-L179]
>
> So currently, any JS app that uses tree-shaking and depends on `apache-arrow`
> or the ESM variants will throw if any of those methods are called, e.g. in my
> case I see `TypeError: e._chunks[t].get is not a function` when calling
> `table.get`.
>
> Indeed switching to the CJS variants like `@apache-arrow/es2015-cjs` fixes
> the issue, since the Arrow build does not inject `sideEffects: false` into
> its package.json for non-ESM variants.
>
> For reference, the `sideEffects: false` logic was introduced in this PR and
> issue:
> [https://github.com/apache/arrow/pull/8418/]
> https://issues.apache.org/jira/browse/ARROW-10255
>
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