perf(dev): warm a single fork by default, overridable with NUXT_DEV_FORK_POOL_SIZE

Author: danielroe

packages/nuxt-cli/src/commands/dev.ts

@@ -171,7 +171,7 @@ const command = defineCommand({
 
 constpool=newForkPool({
 rawArgs: ctx.rawArgs,
-poolSize: 2,
+poolSize: resolveForkPoolSize(),
  listenOverrides,
  inspect,
 })
@@ -276,6 +276,19 @@ function setupSignalHandlers(close: () => Promise<void>): void {
 }
 }
 
+functionresolveForkPoolSize(): number|undefined{
+constraw=process.env.NUXT_DEV_FORK_POOL_SIZE
+if(!raw){
+returnundefined
+}
+constparsed=Number(raw)
+if(!Number.isInteger(parsed)||parsed<0){
+logger.warn(`Ignoring invalid \`NUXT_DEV_FORK_POOL_SIZE=${raw}\`; expected a non-negative integer.`)
+returnundefined
+}
+returnparsed
+}
+
 functionparsePositiveInteger(value: string|undefined): number|undefined{
 constparsed=Number(value)
 if(!value||!Number.isInteger(parsed)||parsed<=0){

packages/nuxt-cli/src/dev/pool.ts

@@ -30,7 +30,7 @@ export class ForkPool {
 
 constructor(options: ForkPoolOptions){
 this.rawArgs=options.rawArgs
-this.poolSize=options.poolSize??2
+this.poolSize=options.poolSize??1
 this.listenOverrides=options.listenOverrides
 this.inspect=options.inspect
 

packages/nuxt-cli/test/unit/fork-pool.spec.ts

@@ -28,6 +28,13 @@ afterEach(async () => {
 })
 
 describe('forkPool',()=>{
+it('should warm a single fork by default',{timeout: 30_000},async()=>{
+constpool=createPool()
+pool.startWarming()
+awaitwaitForReady(pool,1)
+expect(pool.getStats().total).toBe(1)
+})
+
 it('should kill every fork on shutdown',{timeout: 30_000},async()=>{
 constpool=createPool(3)
 pool.startWarming()