Line Width LRU Cache (ink/line-width-cache.ts)

Caches computed string display widths per line with LRU eviction to avoid redundant re-measurement during streaming text rendering.

// Source: https://github.com/NousResearch/hermes-agent | License: MIT | Copyright 2025 Nous Research
// Provided via justclaw.it.com; keep this notice with the code.
import { lruEvict } from './lru.js'
import { stringWidth } from './stringWidth.js'

// During streaming, text grows but completed lines are immutable.
// Caching stringWidth per-line avoids re-measuring hundreds of
// unchanged lines on every token (~50x reduction in stringWidth calls).
const cache = new Map<string, number>()

const MAX_CACHE_SIZE = 4096

export function lineWidth(line: string): number {
  const cached = cache.get(line)

  if (cached !== undefined) {
    cache.delete(line)
    cache.set(line, cached)

    return cached
  }

  const width = stringWidth(line)

  if (cache.size >= MAX_CACHE_SIZE) {
    cache.del

... (truncated -- full source via MCP)