Less template literal and string literal reduction by PranavSenthilnathan · Pull Request #56165 · microsoft/TypeScript

Pranav Senthilnathan (PranavSenthilnathan) · 2023-10-20T20:39:48Z

Checking perf impact of the naive change.

Pranav Senthilnathan (PranavSenthilnathan) · 2023-10-20T20:44:04Z

TypeScript Bot (@typescript-bot) test this
TypeScript Bot (@typescript-bot) perf test this
TypeScript Bot (@typescript-bot) user test this

Jake Bailey (jakebailey) · 2023-10-20T20:48:25Z

TypeScript Bot (@typescript-bot) test this
TypeScript Bot (@typescript-bot) perf test this
TypeScript Bot (@typescript-bot) user test this

I don't think you're on the author list so that doesn't work, though maybe it's some other list that does it.

TypeScript Bot (typescript-bot) · 2023-10-20T20:48:28Z

Heya Jake Bailey (@jakebailey), I've started to run the regular perf test suite on this PR at 8e76d16. You can monitor the build here.

Update: The results are in!

TypeScript Bot (typescript-bot) · 2023-10-20T20:48:28Z

Heya Jake Bailey (@jakebailey), I've started to run the diff-based user code test suite on this PR at 8e76d16. You can monitor the build here.

Update: The results are in!

Jake Bailey (jakebailey) · 2023-10-20T20:51:07Z

What test case are you looking at for this? #52345?

Pranav Senthilnathan (PranavSenthilnathan) · 2023-10-20T20:57:17Z

Updated comment. It's #56081

TypeScript Bot (typescript-bot) · 2023-10-20T21:05:10Z

Jake Bailey (@jakebailey) Here are the results of running the user test suite comparing main and refs/pull/56165/merge:

There were infrastructure failures potentially unrelated to your change:

3 instances of "Package install failed"
1 instance of "Unknown failure"

Otherwise...

Everything looks good!

TypeScript Bot (typescript-bot) · 2023-10-20T21:08:18Z

Jake Bailey (@jakebailey)
The results of the perf run you requested are in!

Here they are:

Compiler

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Angular - node (v18.15.0, x64)}
_{Memory used}	_{295,123k (± 0.01%)}	_{295,097k (± 0.01%)}	_~	_295,046k	_295,160k	_{p=0.199 n=6}
_{Parse Time}	_{2.63s (± 0.57%)}	_{2.63s (± 0.29%)}	_~	_2.62s	_2.64s	_{p=0.503 n=6}
_{Bind Time}	_{0.84s (± 0.90%)}	_{0.84s (± 1.30%)}	_~	_0.83s	_0.85s	_{p=0.865 n=6}
_{Check Time}	_{8.06s (± 0.31%)}	_{8.06s (± 0.29%)}	_~	_8.03s	_8.10s	_{p=0.935 n=6}
_{Emit Time}	_{7.08s (± 0.12%)}	_{7.06s (± 0.29%)}	_~	_7.03s	_7.08s	_{p=0.119 n=6}
_{Total Time}	_{18.61s (± 0.14%)}	_{18.58s (± 0.19%)}	_~	_18.53s	_18.63s	_{p=0.076 n=6}
_{Compiler-Unions - node (v18.15.0, x64)}
_{Memory used}	_{192,610k (± 1.56%)}	_{193,587k (± 1.64%)}	_~	_190,674k	_196,533k	_{p=0.471 n=6}
_{Parse Time}	_{1.35s (± 1.30%)}	_{1.36s (± 1.27%)}	_~	_1.34s	_1.38s	_{p=0.278 n=6}
_{Bind Time}	_{0.73s (± 0.00%)}	_{0.73s (± 0.00%)}	_~	_0.73s	_0.73s	_{p=1.000 n=6}
_{Check Time}	_{9.18s (± 0.17%)}	_{9.19s (± 0.34%)}	_~	_9.13s	_9.21s	_{p=0.413 n=6}
_{Emit Time}	_{2.65s (± 0.52%)}	_{2.63s (± 0.40%)}	_~	_2.62s	_2.65s	_{p=0.161 n=6}
_{Total Time}	_{13.90s (± 0.22%)}	_{13.91s (± 0.17%)}	_~	_13.88s	_13.93s	_{p=0.569 n=6}
_{Monaco - node (v18.15.0, x64)}
_{Memory used}	_{347,301k (± 0.00%)}	_{347,299k (± 0.00%)}	_~	_347,276k	_347,314k	_{p=0.630 n=6}
_{Parse Time}	_{2.46s (± 0.33%)}	_{2.46s (± 0.60%)}	_~	_2.44s	_2.48s	_{p=0.508 n=6}
_{Bind Time}	_{0.94s (± 0.43%)}	_{0.94s (± 0.00%)}	_~	_0.94s	_0.94s	_{p=0.405 n=6}
_{Check Time}	_{6.92s (± 0.33%)}	_{6.92s (± 0.32%)}	_~	_6.90s	_6.96s	_{p=1.000 n=6}
_{Emit Time}	_{4.02s (± 0.44%)}	_{4.02s (± 0.27%)}	_~	_4.01s	_4.04s	_{p=0.806 n=6}
_{Total Time}	_{14.34s (± 0.17%)}	_{14.34s (± 0.27%)}	_~	_14.30s	_14.40s	_{p=0.935 n=6}
_{TFS - node (v18.15.0, x64)}
_{Memory used}	_{302,535k (± 0.01%)}	_{302,526k (± 0.01%)}	_~	_302,486k	_302,541k	_{p=0.688 n=6}
_{Parse Time}	_{2.00s (± 0.73%)}	_{2.00s (± 0.52%)}	_~	_1.99s	_2.02s	_{p=1.000 n=6}
_{Bind Time}	_{1.00s (± 0.00%)}	_{1.01s (± 1.46%)}	_~	_0.99s	_1.03s	_{p=0.295 n=6}
_{Check Time}	_{6.26s (± 0.42%)}	_{6.25s (± 0.54%)}	_~	_6.22s	_6.31s	_{p=0.573 n=6}
_{Emit Time}	_{3.56s (± 0.58%)}	_{3.56s (± 0.50%)}	_~	_3.53s	_3.58s	_{p=0.570 n=6}
_{Total Time}	_{12.81s (± 0.17%)}	_{12.82s (± 0.17%)}	_~	_12.79s	_12.85s	_{p=0.571 n=6}
_{material-ui - node (v18.15.0, x64)}
_{Memory used}	_{470,481k (± 0.00%)}	_{470,483k (± 0.00%)}	_~	_470,453k	_470,504k	_{p=0.688 n=6}
_{Parse Time}	_{2.58s (± 0.53%)}	_{2.58s (± 0.62%)}	_~	_2.56s	_2.61s	_{p=0.315 n=6}
_{Bind Time}	_{1.00s (± 1.21%)}	_{0.99s (± 1.22%)}	_~	_0.98s	_1.01s	_{p=0.680 n=6}
_{Check Time}	_{16.62s (± 0.34%)}	_{16.59s (± 0.29%)}	_~	_16.52s	_16.66s	_{p=0.470 n=6}
_{Emit Time}	_{0.00s (± 0.00%)}	_{0.00s (± 0.00%)}	_~	_0.00s	_0.00s	_{p=1.000 n=6}
_{Total Time}	_{20.19s (± 0.38%)}	_{20.17s (± 0.28%)}	_~	_20.08s	_20.25s	_{p=0.575 n=6}
_{xstate - node (v18.15.0, x64)}
_{Memory used}	_{512,617k (± 0.01%)}	_{512,621k (± 0.01%)}	_~	_512,558k	_512,726k	_{p=0.936 n=6}
_{Parse Time}	_{3.27s (± 0.42%)}	_{3.28s (± 0.32%)}	_~	_3.26s	_3.29s	_{p=0.241 n=6}
_{Bind Time}	_{1.55s (± 0.26%)}	_{1.55s (± 0.53%)}	_~	_1.53s	_1.55s	_{p=0.218 n=6}
_{Check Time}	_{2.88s (± 1.49%)}	_{2.86s (± 1.01%)}	_~	_2.82s	_2.89s	_{p=0.574 n=6}
_{Emit Time}	_{0.08s (± 0.00%)}	_{0.08s (± 0.00%)}	_~	_0.08s	_0.08s	_{p=1.000 n=6}
_{Total Time}	_{7.77s (± 0.68%)}	_{7.75s (± 0.38%)}	_~	_7.70s	_7.78s	_{p=0.521 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

Angular - node (v18.15.0, x64)
Compiler-Unions - node (v18.15.0, x64)
Monaco - node (v18.15.0, x64)
TFS - node (v18.15.0, x64)
material-ui - node (v18.15.0, x64)
xstate - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

tsserver

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{Compiler-UnionsTSServer - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{2,376ms (± 1.44%)}	_{2,360ms (± 1.26%)}	_~	_2,335ms	_2,412ms	_{p=0.575 n=6}
_{Req 2 - geterr}	_{5,339ms (± 1.13%)}	_{5,446ms (± 1.13%)}	_{+107ms (+ 2.01%)}	_5,322ms	_5,483ms	_{p=0.016 n=6}
_{Req 3 - references}	_{326ms (± 0.19%)}	_{327ms (± 0.81%)}	_~	_325ms	_332ms	_{p=0.557 n=6}
_{Req 4 - navto}	_{278ms (± 1.26%)}	_{273ms (± 1.29%)}	_~	_271ms	_280ms	_{p=0.115 n=6}
_{Req 5 - completionInfo count}	_{1,356 (± 0.00%)}	_{1,356 (± 0.00%)}	_~	_1,356	_1,356	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{78ms (± 4.93%)}	_{86ms (± 7.24%)}	_~	_74ms	_90ms	_{p=0.075 n=6}
_{CompilerTSServer - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{2,490ms (± 1.06%)}	_{2,488ms (± 1.07%)}	_~	_2,455ms	_2,533ms	_{p=0.810 n=6}
_{Req 2 - geterr}	_{4,113ms (± 2.06%)}	_{4,127ms (± 1.78%)}	_~	_4,055ms	_4,219ms	_{p=0.378 n=6}
_{Req 3 - references}	_{340ms (± 1.61%)}	_{341ms (± 1.74%)}	_~	_333ms	_348ms	_{p=0.934 n=6}
_{Req 4 - navto}	_{284ms (± 0.29%)}	_{285ms (± 0.48%)}	_~	_283ms	_287ms	_{p=0.865 n=6}
_{Req 5 - completionInfo count}	_{1,518 (± 0.00%)}	_{1,518 (± 0.00%)}	_~	_1,518	_1,518	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{84ms (± 6.63%)}	_{84ms (± 6.77%)}	_~	_77ms	_89ms	_{p=1.000 n=6}
_{xstateTSServer - node (v18.15.0, x64)}
_{Req 1 - updateOpen}	_{2,592ms (± 0.97%)}	_{2,595ms (± 0.63%)}	_~	_2,569ms	_2,619ms	_{p=0.748 n=6}
_{Req 2 - geterr}	_{1,672ms (± 2.68%)}	_{1,711ms (± 1.18%)}	_~	_1,686ms	_1,734ms	_{p=0.173 n=6}
_{Req 3 - references}	_{113ms (± 9.51%)}	_{121ms (± 8.93%)}	_~	_105ms	_128ms	_{p=0.220 n=6}
_{Req 4 - navto}	_{359ms (± 0.45%)}	_{362ms (± 0.77%)}	_~	_359ms	_367ms	_{p=0.101 n=6}
_{Req 5 - completionInfo count}	_{2,073 (± 0.00%)}	_{2,073 (± 0.00%)}	_~	_2,073	_2,073	_{p=1.000 n=6}
_{Req 5 - completionInfo}	_{302ms (± 2.18%)}	_{304ms (± 1.93%)}	_~	_297ms	_313ms	_{p=0.520 n=6}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

CompilerTSServer - node (v18.15.0, x64)
Compiler-UnionsTSServer - node (v18.15.0, x64)
xstateTSServer - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Startup

Comparison Report - baseline..pr

_Metric	_baseline	_pr	_Delta	_Best	_Worst	_p-value
_{tsc-startup - node (v18.15.0, x64)}
_{Execution time}	_{152.53ms (± 0.18%)}	_{152.36ms (± 0.19%)}	_{-0.17ms (- 0.11%)}	_151.08ms	_156.17ms	_{p=0.000 n=600}
_{tsserver-startup - node (v18.15.0, x64)}
_{Execution time}	_{227.29ms (± 0.15%)}	_{227.18ms (± 0.16%)}	_{-0.10ms (- 0.05%)}	_225.95ms	_232.25ms	_{p=0.001 n=600}
_{tsserverlibrary-startup - node (v18.15.0, x64)}
_{Execution time}	_{228.45ms (± 0.17%)}	_{228.35ms (± 0.15%)}	_~	_226.47ms	_232.80ms	_{p=0.077 n=600}
_{typescript-startup - node (v18.15.0, x64)}
_{Execution time}	_{228.73ms (± 0.15%)}	_{228.79ms (± 0.15%)}	_~	_227.44ms	_231.94ms	_{p=0.092 n=600}

System info unknown

Hosts

node (v18.15.0, x64)

Scenarios

tsc-startup - node (v18.15.0, x64)
tsserver-startup - node (v18.15.0, x64)
tsserverlibrary-startup - node (v18.15.0, x64)
typescript-startup - node (v18.15.0, x64)

_Benchmark	_Name	_Iterations
_Current	_pr	₆
_Baseline	_baseline	₆

Developer Information:

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…ranas/template-literal-reduction

Pranav Senthilnathan (PranavSenthilnathan) · 2023-10-27T02:20:20Z

So this is not the solution since this was an intentional feature introduced in #41276. But I think there should probably be some middle ground between reducing eagerly during union creation and lazily when subtype reduction is performed. Maybe just doing subtype reduction when checking variable declaration nodes?

Jake Bailey (jakebailey) · 2023-10-27T02:45:31Z

The main problem is that if we don't always reduce, then two unions that are actually the same thing can be present at once, which means you can't fast check for equality and such (maybe some other invariants).

TypeScript Bot (typescript-bot) · 2026-03-24T21:18:29Z

With 6.0 out as the final release vehicle for this codebase, we're closing all PRs that don't fit the merge criteria for post-6.0 patches. If you think this was a mistake and this PR fits the post-6.0 patch criteria, please post to the 6.0 iteration issue with details (specifically, which PR and which patch criteria it satisfies).

Next steps for PRs:

For crash bugfixes or language service improvements, PRs are currently accepted at the typescript-go repo
Changes to type system behavior should wait until after 7.0, at which point mainline TypeScript development will resume in this repository with the Go codebase
Library file updates (lib.d.ts etc) continue to live in this repo or the DOM Generator repo as appropriate

naive perf change
8e76d16

TypeScript Bot (typescript-bot) added the For Uncommitted Bug PR for untriaged, rejected, closed or missing bug label Oct 20, 2023

TypeScript Bot (typescript-bot) assigned Pranav Senthilnathan (PranavSenthilnathan)Oct 20, 2023

TypeScript Bot (typescript-bot) added For Milestone Bug PRs that fix a bug with a specific milestone and removed For Uncommitted Bug PR for untriaged, rejected, closed or missing bug labels Oct 20, 2023

Pranav Senthilnathan (PranavSenthilnathan) added 2 commits October 26, 2023 17:45

update tests/baselines
fc09243

Merge branch 'main' ofhttps://github.com/microsoft/TypeScriptinto p…
339d83e
…ranas/template-literal-reduction

TypeScript Bot (typescript-bot) closed this Mar 24, 2026

Jake Bailey (jakebailey) deleted the pranas/template-literal-reduction branch August 28, 2026 19:52

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Less template literal and string literal reduction - #56165

Less template literal and string literal reduction#56165
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