Experimental populate-icon-defs optimization

I observed the current populate-icon-defs.js script being OOM killed,
having used 7.5MB of memory.

This version now:

* Uses `rg` to do the grepping, which should be fast and highly memory efficient.
* Loads only the required icons from npm

Local testing shows it emits the same results, though slightly re-ordered.

Author: osfameron

scripts/populate-icon-defs

@@ -0,0 +1,18 @@
+#!/bin/bash
+set -euo pipefail
+
+RG='rg --no-heading --no-messages --only-matching --no-line-number --no-filename --type html'
+OUT=$(mktemp)
+
+siteDir=./public
+
+(
+    # Capture FA5 class usage (fas|far|fal|fab)
+    $RG 'fa[brs]?\s+fa-[a-z0-9-]+' $siteDir || true
+
+    # Capture FA6 class usage (fa-solid|fa-regular|fa-light|fa-brands)
+    $RG 'fa-(solid|regular|light|brands)\s+fa-[a-z0-9-]+' $siteDir || true
+) | sort | uniq > $OUT
+
+node scripts/populate-icon-defs-lean.js $OUT $siteDir
+echo DONE

scripts/populate-icon-defs-lean.js

@@ -0,0 +1,143 @@
+'use strict'
+
+// Usage:
+//   node scripts/populate-icon-defs-lean.js [siteDir=public]
+// Notes:
+
+const fs = require('fs')
+const ospath = require('path')
+
+
+const REQUIRED_ICON_NAMES_RX = /\biconNames: *(\[.*?\])/s
+
+function camelCase (str) {
+  return str.replace(/-(.)/g, (_, l) => l.toUpperCase())
+}
+
+function tryResolve (moduleId) {
+  try { require.resolve(moduleId); return true } catch { return false }
+}
+
+function loadStubRequiredIcons (iconDefsFile) {
+  try {
+    const contents = fs.readFileSync(iconDefsFile, 'utf8')
+    const m = contents.match(REQUIRED_ICON_NAMES_RX)
+    if (!m) return { required: [], comment: null }
+    const json = m[1].replace(/'/g, '"')
+    const required = JSON.parse(json)
+    // Reconstruct a comment to preserve the stub’s intent in the generated file
+    const comment = `/*! iconNames: [${required.map((s) => `'${s}'`).join(', ')}] */`
+    return { required, comment }
+  } catch {
+    return { required: [], comment: null }
+  }
+}
+
+// v4 shim map: converts 'fa fa-<name>' to real prefix/name
+const iconShims = require('@fortawesome/fontawesome-free/js/v4-shims').reduce((accum, it) => {
+  accum['fa-' + it[0]] = [it[1] || 'fas', 'fa-' + (it[2] || it[0])]
+  return accum
+}, {})
+
+function applyShimIfV4 (prefix, iconName) {
+  if (prefix !== 'fa') return [prefix, iconName]
+  const shim = iconShims[iconName]
+  if (!shim) return [prefix, iconName]
+  const [realPrefix, realIconName] = shim
+  return [realPrefix, realIconName]
+}
+
+function pkgBaseForPrefix (prefix) {
+  // Prefer Pro if available, else Free
+  const pro = {
+    fa: '@fortawesome/pro-solid-svg-icons/',
+    fas: '@fortawesome/pro-solid-svg-icons/',
+    far: '@fortawesome/pro-regular-svg-icons/',
+    fal: '@fortawesome/pro-light-svg-icons/',
+  }[prefix]
+  const free = {
+    fa: '@fortawesome/free-solid-svg-icons/',
+    fas: '@fortawesome/free-solid-svg-icons/',
+    far: '@fortawesome/free-regular-svg-icons/',
+    fab: '@fortawesome/free-brands-svg-icons/',
+  }[prefix]
+  if (pro && tryResolve(pro)) return pro
+  if (free && tryResolve(free)) return free
+  return null
+}
+
+function loadIcon (pfx, name) {
+
+  const camel = camelCase(name) // 'fa-coffee' -> 'faCoffee'
+  const base = pkgBaseForPrefix(pfx)
+  if (!base) return null
+  const modPath = base + camel
+  if (!tryResolve(modPath)) return null
+  const mod = require(modPath)
+  const def = mod[camel]
+  return def ? { ...def, prefix: pfx } : null
+}
+
+function uniq (arr) {
+  const seen = {}
+  return arr.filter((it) => {
+    if (seen[it]) return false
+    seen[it] = true
+    return true
+  })
+}
+
+async function main () {
+  const iconsList = process.argv[2]
+  if (! iconsList) {
+    throw new Error("Missing iconsList argument")
+  }
+
+  const siteDir = process.argv[3] || 'public'
+
+  const iconDefsFile = ospath.join(siteDir, '_/js/vendor/fontawesome-icon-defs.js')
+
+  const iconKeys = fs.readFileSync(iconsList, 'utf8')
+    .split('\n')
+    .map((line) => line.trim())
+    .filter((line) => line.length > 0)
+
+  const {
+    required: stubRequired,
+    comment: stubComment } = loadStubRequiredIcons(iconDefsFile)
+
+  const icons = uniq(
+    [...iconKeys, ...stubRequired].map(
+      (iconKey) => {
+        const [prefix, iconName] = iconKey.split(' ')
+        const [realPrefix, realIconName] = applyShimIfV4(prefix, iconName)
+        return [realPrefix,realIconName]
+      }
+  ))
+
+  // Resolve and load per-icon defs
+  const defs = []
+  const seen = new Set()
+  for (let [prefix,iconName] of icons) {
+    const def = loadIcon(prefix, iconName)
+    if (def) {
+      const k = def.prefix + ' ' + iconName
+      if (!seen.has(k)) { defs.push(def); seen.add(k) }
+    } else if (prefix === 'fal') {
+      console.log(`FontAwesome Light icon missing or Pro not installed: ${iconKey}`)
+    }
+    else {
+        console.log(`Icon not found: ${iconKey}`)
+    }
+  }
+
+  // iconNames: ['far fa-copy', 'fas fa-link', 'fab fa-github', 'fas fa-terminal', 'fal fa-external-link-alt']
+  fs.writeFileSync(iconDefsFile, 
+    `${stubComment || ''}
+     window.fontawesomeIconDefs = ${JSON.stringify(defs)}\n`,
+    'utf8')
+
+  console.log(`Wrote ${defs.length} icon defs to ${iconDefsFile}`)
+}
+
+main().catch((e) => { console.error(e); process.exit(1) })