Perf: Cache styles to avoid creating new object style every execution #250
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Actionable comments posted: 2
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Files selected for processing (1)
- packages/mobile/src/styles/builder/builder.ts (1 hunks)
Additional comments not posted (7)
packages/mobile/src/styles/builder/builder.ts (7)
180-180: Sorting definitions improves cache consistency.Sorting the definitions ensures that the order of input doesn't affect the cache key, leading to consistent key generation.
182-185: Key generation logic is sound.The key generation logic concatenates sorted definitions into a single string, which is used as the cache key. This approach is effective for ensuring unique keys for different style combinations.
186-187: Check for existing cached styles.The code checks if the styles are already cached using the generated key. If found, it returns the cached styles, improving performance by avoiding redundant calculations.
190-193: Merge base definitions into styles.The loop merges base definitions into the
stylesobject. Ensure that thegetmethod returns valid style objects.
197-200: Merge conditional definitions into styles.The loop merges conditional definitions into the
stylesobject if they are not null, undefined, or true. Ensure that thegetmethod handles these cases correctly.
204-204: Cache the computed styles.The computed styles are cached using the generated key, ensuring that future requests for the same styles are served from the cache.
205-205: Return the computed styles.The method returns the computed styles, either from the cache or newly computed.
| const allDefinitions = [ | ||
| ...(definitions || []), | ||
| ...(conditionalDefinitions || []), | ||
| ].filter((definition) => typeof definition === "string"); |
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Ensure definitions are not null or undefined.
The code concatenates definitions and conditionalDefinitions and filters out non-string values. Ensure that definitions and conditionalDefinitions are not null or undefined before concatenation.
- const allDefinitions = [
- ...(definitions || []),
- ...(conditionalDefinitions || []),
- ].filter((definition) => typeof definition === "string");
+ const allDefinitions = [
+ ...(definitions ?? []),
+ ...(conditionalDefinitions ?? []),
+ ].filter((definition) => typeof definition === "string");Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| const allDefinitions = [ | |
| ...(definitions || []), | |
| ...(conditionalDefinitions || []), | |
| ].filter((definition) => typeof definition === "string"); | |
| const allDefinitions = [ | |
| ...(definitions ?? []), | |
| ...(conditionalDefinitions ?? []), | |
| ].filter((definition) => typeof definition === "string"); |
| ); | ||
| let styles = this.cached.get(keyStyle); | ||
| if (styles) return styles; | ||
|
|
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Ensure styles initialization.
Before merging styles, ensure that the styles variable is properly initialized.
- let styles = this.cached.get(keyStyle);
- if (styles) return styles;
+ let styles = this.cached.get(keyStyle) || {};
+ if (Object.keys(styles).length > 0) return styles;Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| let styles = this.cached.get(keyStyle) || {}; | |
| if (Object.keys(styles).length > 0) return styles; |
On every render, the
flattenmethod will be executed, returning the appropriate styles fromStyleSheet.flatten. However,StyleSheet.flattencreates and returns a new object on each execution, as seen here:https://github.com/facebook/react-native/blob/8408b8bc96db15e265ca65fce7875ee65dcfdcec/packages/react-native/Libraries/StyleSheet/flattenStyle.js#L29
To avoid this, we can cache the created styles and reuse them if the same style is needed again. This approach provides the same benefits as using
StyleSheet.createor declaring a styles object outside of the render method.Summary by CodeRabbit