fetch: improve regexes in data-uri.js #4483
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Co-authored-by: tsctx <[email protected]>
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Pull Request Overview
This PR improves regex patterns in the data-url.js file to address performance issues identified by SonarJS. The changes focus on optimizing regex patterns and refactoring a for loop to a while loop.
- Adds the
uflag to regex patterns for better Unicode handling and performance - Optimizes character class ordering and grouping in regex patterns
- Refactors a for loop to a while loop in the percentDecode function
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| @@ -86,7 +86,7 @@ function dataURLProcessor (dataURL) { | |||
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| // 5. Remove trailing U+0020 SPACE code points from mimeType, | |||
| // if any. | |||
| mimeType = mimeType.replace(/(\u0020)+$/, '') | |||
| mimeType = mimeType.replace(/(\u0020+)$/u, '') | |||
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The capturing group (\u0020+) is unnecessary since $1 is not used in the replacement. Use a non-capturing group instead: /(?:\u0020+)$/u or simply /\u0020+$/u
| mimeType = mimeType.replace(/(\u0020+)$/u, '') | |
| mimeType = mimeType.replace(/\u0020+$/u, '') |
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| @@ -572,7 +574,7 @@ function serializeAMimeType (mimeType) { | |||
| if (!HTTP_TOKEN_CODEPOINTS.test(value)) { | |||
| // 1. Precede each occurrence of U+0022 (") or | |||
| // U+005C (\) in value with U+005C (\). | |||
| value = value.replace(/(\\|")/g, '\\$1') | |||
| value = value.replace(/[\\"]/ug, '\\$&') | |||
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The g flag is redundant when combined with the u flag for this specific pattern. The u flag alone is sufficient for Unicode support, and g should only be used when multiple replacements are needed.
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sonarjs was reporting some imperformance in the regexes
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