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Checks for JavaScript files that exceed recommended size limits
Rule IDperf/js-file-size
CategoryPerformance
ScopeSite-wide
Severityerror
Weight7/10

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Solution

Large JavaScript files block the main thread and delay interactivity. Code-split bundles into smaller chunks, tree-shake unused exports, lazy-load non-critical scripts, and defer or async load third-party scripts. Use dynamic imports for route-based splitting.

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Options

This rule supports the following configuration options:
OptionTypeDefaultDescription
warn_bytesnumber256000 (250KB)Byte size to trigger warning
error_bytesnumber1048576 (1MB)Byte size to trigger error

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Configuration Example

squirrel.toml
[rules."perf/js-file-size"]
warn_bytes = 256000
error_bytes = 1048576

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Enable / Disable

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Disable this rule

squirrel.toml
[rules]
disable = ["perf/js-file-size"]

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Disable all Performance rules

squirrel.toml
[rules]
disable = ["perf/*"]

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Enable only this rule

squirrel.toml
[rules]
enable = ["perf/js-file-size"]
disable = ["*"]