evanw/esbuild · error · Error

Cannot call "initialize" more than once

Error message

Cannot call "initialize" more than once

What it means

Error "Cannot call "initialize" more than once" thrown in evanw/esbuild.

Source

Thrown at lib/npm/node.ts:238

    callback: (err, res) => { if (err) throw err; result = res! },
  }))
  return result!
}

export const stop = () => {
  if (stopService) stopService()
  if (workerThreadService) workerThreadService.stop()
  return Promise.resolve()
}

let initializeWasCalled = false

export let initialize: typeof types.initialize = options => {
  options = common.validateInitializeOptions(options || {})
  if (options.wasmURL) throw new Error(`The "wasmURL" option only works in the browser`)
  if (options.wasmModule) throw new Error(`The "wasmModule" option only works in the browser`)
  if (options.worker) throw new Error(`The "worker" option only works in the browser`)
  if (initializeWasCalled) throw new Error('Cannot call "initialize" more than once')
  ensureServiceIsRunning()
  initializeWasCalled = true
  return Promise.resolve()
}

interface Service {
  build: typeof types.build
  context: typeof types.context
  transform: typeof types.transform
  formatMessages: typeof types.formatMessages
  analyzeMetafile: typeof types.analyzeMetafile
}

let defaultWD = process.cwd()
let longLivedService: Service | undefined
let stopService: (() => void) | undefined

let ensureServiceIsRunning = (): Service => {

View on GitHub (pinned to 6ff1d8b0d8)

Solutions

1. Call "initialize" only once at startup before using the esbuild API
2. Remove duplicate "initialize" calls; subsequent calls are unnecessary once initialization completes

Example fix

// Call initialize exactly once before any other API usage
await esbuild.initialize({});
await esbuild.transform(code, { loader: 'ts' });

When it happens

Trigger: Thrown at lib/npm/node.ts:238 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of evanw/esbuild@6ff1d8b0d8 (2026-08-03). Data as JSON: /data/errors/14a596f7ecd9d145.json. Report an issue: GitHub.