awesome-reviewers/_reviewers/typescript-cache-expensive-computed-values.md

title, description, repository, label, language, comments_count, repository_stars

title	description	repository	label	language	comments_count	repository_stars
Cache expensive computed values	Cache frequently accessed or computed values to avoid redundant calculations and property lookups. This applies to: 1. Loop invariant values 2. Expensive computations	microsoft/typescript	Performance Optimization	TypeScript	4	105378

Cache frequently accessed or computed values to avoid redundant calculations and property lookups. This applies to:

1. Loop invariant values
2. Expensive computations
3. Repeated property access
4. Function call results

Example - Before:

while (index < path.length) {
    // path.length accessed on every iteration
    if (path.indexOf(separator, index) !== -1) {
        // indexOf called multiple times
    }
}

Example - After:

const pathLength = path.length; // Cache loop invariant
const separatorIndex = path.indexOf(separator, index); // Cache computation
while (index < pathLength) {
    if (separatorIndex !== -1) {
        // Use cached values
    }
}

This optimization is particularly important in performance-critical paths and loops. When implementing, consider:

• Caching loop invariants outside the loop
• Storing repeated computation results in local variables
• Caching property accesses that won't change during execution
• Using local variables for values accessed multiple times

The performance impact can be significant, especially when the cached values are used frequently or the computations are expensive.