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feat(aws-cdk-lib): reduce JavaScript load time, second attempt #27362
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This change halves the load time of `require('aws-cdk-lib')`, from ~600ms to ~300ms on my machine. It also shaves ~8min off running all integ tests (again, on my machine). It does this by making all loading of JavaScript modules lazy, so they are only loaded just before any symbols from them are actually accessed (instead of loading all modules at startup). This new automatic module replaces the previous manual effort to do something similar, in `lazy-index.ts`. Note that this transformation (unfortunately) does not affect TypeScript compilation times: the TypeScript compiler is still going to read all `.d.ts` files. To improve interactive TypeScript performance, use `swc` or `ts-node` with type checking disabled. Fully type checking your application using `tsc` will take the amount of time it takes. Turning this: ```js const x = require("x"); module.exports.banana = function() { return x.hello(); } ``` Into this: ```js var x = () => { var tmp = require("x"); x = () => tmp; return tmp; }; module.exports.banana = function () { return x().hello(); }; ```
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This is a re-roll of #27217 which had to be reverted (first attempt to fix forward in #27314, then reverted in #27353).
The issue with the previous change were:
cjs-module-lexer
.We now generate code that passes the
cjs-module-lexer
, and have tests in place to prove it.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license