Pierre Gayvallet 8453fe820a Cleanup spread operators in reduce calls (#157471) ... ## Summary The spread operator is costly and put pressure on GC. It should be avoided when possible, especially in loops. This PR adapts a lot of `reduce` calls in the codebase to remove the usages of the diabolic spread operator, when possible. Note: the PR is not fully exhaustive. I focused on the server-side, as we're more directly impacted than on browser-side code regarding performances. ## Removing `...` usages in `kittens.reduce()` For `reduce` loops, the spread operator can usually easily be replaced: #### - setting a value on the accum object and returning it #### BAD ```ts return this.toArray().reduce( (acc, renderer) => ({ ...acc, [renderer.name]: renderer, }), {} as Record<string, ExpressionRenderer> ); ``` #### GOOD ```ts return this.toArray().reduce((acc, renderer) => { acc[renderer.name] = renderer; return acc; }, {} as Record<string, ExpressionRenderer>); ``` #### - assigning values to the accum object and returning it #### BAD ```ts const allAggs: Record<string, any> = fieldAggRequests.reduce( (aggs: Record<string, any>, fieldAggRequest: unknown | null) => { return fieldAggRequest ? { ...aggs, ...(fieldAggRequest as Record<string, any>) } : aggs; }, {} ); ``` #### GOOD ```ts const allAggs = fieldAggRequests.reduce<Record<string, any>>( (aggs: Record<string, any>, fieldAggRequest: unknown | null) => { if (fieldAggRequest) { Object.assign(aggs, fieldAggRequest); } return aggs; }, {} ); ``` #### - pushing items to the accum list and returning it #### BAD ```ts const charsFound = charToArray.reduce( (acc, char) => (value.includes(char) ? [...acc, char] : acc), [] as string[] ); ``` #### GOOD ```ts const charsFound = charToArray.reduce((acc, char) => { if (value.includes(char)) { acc.push(char); } return acc; }, [] as string[]); ``` ## Questions #### Are you sure all the changes in this are strictly better for runtime performances? Yes, yes I am. #### How much better? Likely not much. #### Are you planning on analyzing the perf gain? Nope. #### So why did you do it? I got tired of seeing badly used spread operators in my team's owned code, and I had some extra time during on-week, so I spent a few hours adapting the usages in all our runtime/production codebase. #### Was it fun? Take your best guess. --------- Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>		2023-05-22 04:50:24 -07:00
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core-node-server	[Migrations] Add migrator node role (#151978)	2023-02-27 06:49:31 -07:00
core-node-server-internal	Cleanup spread operators in reduce calls (#157471)	2023-05-22 04:50:24 -07:00
core-node-server-mocks	[Migrations] Add migrator node role (#151978)	2023-02-27 06:49:31 -07:00