feat(scripts): Create script to help with CJS -> ESM migration #8197
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This is based on js2ts, but considerably simplified since we no longer need to deal with goog.module IDs.
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PR: feature
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Marking this draft as I want to make a few changes to deal with a few common syntax styles that we use in our CJS modules that we didn't seem to use (or at least: not frequently) in our goog.modules—notably |
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Sweet sweet, please send me a ping when this reopens b/c GitHub doesn't notify! |
Support (optionally renaming) assignments to module.exports, in addition to the existing support for simple exports property assignmenets.
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OK, this is now ready for review. |
scripts/migration/cjs2esm
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| const requireRE = | ||
| /(?:const\s+(?:([$\w]+)|(\{[^}]*\}))\s+=\s+)?require\('([^']+)'\);/g; | ||
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| /** RegExp matching key: value pairs in destructuring assignments. */ | ||
| const keyValueRE = /([$\w]+)\s*:\s*([$\w]+)\s*(?=,|})/g; | ||
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| /** Prefix for RegExp matching a top-level declaration. */ | ||
| const declPrefix = | ||
| '(?:const|let|var|(?:async\\s+)?function(?:\\s+\\*)?|class)'; |
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I'm just gonna trust this is correct.
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I guess I could write …|function|async function|function *|async function *|…
Though actually I just noticed an error: the space between function and * in generator decls is optional.
| if (moduleName[0] === '.') { | ||
| // Relative path. Could check and add '.mjs' suffix if desired. | ||
| } |
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This is mean to be empty?
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Yes. There is a bit of optional code that I might write to save having to fix up import paths manually—the only difficulty is that sometimes the imported filename will be an .mjs and other times it will just be .js, and not even testing file existence can necessarily distinguish because the file in question might be mid-conversion by the same invocation of this tool. So I left this as a placeholder for the moment.
The basics
The details
Proposed Changes
Create script to help with CJS -> ESM migration.
Reason for Changes
We need to finish migrating tests to ESM as the latest version of chai no longer supports loading via require()—see PR #8092.
Test Coverage
Some very cursory manual testing of this script has been done. No changes to testing of Blockly anticipated.
Additional Information
This is based on js2ts, but considerably simplified since we no longer need to deal with goog.module IDs.