facebook/flow · error · Error

Flow not found

Error message

Flow not found

What it means

getFlowPath resolves the flow binary in order: (1) npm-packaged flow-bin in the flowconfig dir / workspace root, (2) the pathToFlow setting resolved against those dirs and looked up on PATH, (3) the extension's bundled flow. Each failure is logged; when every enabled strategy fails it throws the terminal 'Flow not found'.

Source

Thrown at packages/flow-for-vscode/src/utils/getFlowPath.ts:74

    return flowPath;
  } catch (err: any) {
    logger.error(
      `Error loading flow using option 'pathToFlow'\n${err.message}`,
    );
  }

  // 3) if nothing works fallback to bundled flow
  if (useBundledFlow) {
    try {
      const flowPath = getBundledFlowPath();
      logger.info('Falling back to bundled flow.');
      return flowPath;
    } catch (err: any) {
      logger.error(`Failed to load bundled flow.\n${err.message}`);
    }
  }

  throw new Error('Flow not found');
}

async function getNpmPackagedFlow(
  flowconfigDir: string,
  workspaceRoot: string,
  logger: Logger,
): Promise<string> {
  const dirsToCheck = [
    // a) check in flowconfig dir
    flowconfigDir,
    // b) check in workspaceRoot (ignore if flowconfigDir and workspaceRoot same)
    flowconfigDir !== workspaceRoot ? workspaceRoot : null,
  ].filter((v) => v != null);

  for (let i = 0; i < dirsToCheck.length; i += 1) {
    // eslint-disable-next-line no-await-in-loop
    const flowPath = await getFlowBinPath(dirsToCheck[i], logger);
    if (flowPath) {

View on GitHub (pinned to d1341dac89)

Solutions

1. Install flow-bin where the extension looks: `npm install --save-dev flow-bin` in the flowconfig dir or workspace root
2. Set `flow.pathToFlow` to the absolute path of a working flow binary
3. If you disabled bundled flow (`flow.useBundledFlow`), re-enable it or install one of the above
4. Read the Flow output channel: every failed strategy logs its reason before the final throw

Example fix

// before (VS Code settings.json)
{ "flow.pathToFlow": "flow", "flow.useNPMPackagedFlow": false }

// after (VS Code settings.json)
{
  "flow.pathToFlow": "/abs/path/to/project/node_modules/.bin/flow",
  "flow.useNPMPackagedFlow": true
}
// plus: npm install --save-dev flow-bin

import {access} from 'fs/promises';
import path from 'path';

async function flowLikelyResolvable(flowconfigDir: string, workspaceRoot: string): Promise<boolean> {
  const candidates = [
    path.join(flowconfigDir, 'node_modules', '.bin', 'flow'),
    path.join(workspaceRoot, 'node_modules', '.bin', 'flow'),
  ];
  for (const c of candidates) {
    try { await access(c); return true; } catch {}
  }
  return false;
}

try {
  const flowPath = await getFlowPath(params);
} catch (err) {
  if (err instanceof Error && err.message === 'Flow not found') {
    // prompt the user to install flow-bin or configure pathToFlow,
    // then degrade gracefully (no language server)
  } else throw err;
}

When it happens

Trigger: useNPMPackagedFlow enabled but flow-bin not installed in either dir; pathToFlow pointing at a nonexistent command; useBundledFlow disabled or the bundled module missing — or any combination.

Common situations: Fresh clone before `npm install`; pathToFlow set to a global `flow` not on the GUI VS Code process's PATH; bundled flow excluded in custom builds; monorepos where neither flowconfig dir nor workspace root has flow-bin.

Related errors

• '${command}' not found
• Flow version ${version} doesn't support 'flow lsp'. Please u
• Unsupported .flowconfig option `log.file`. The VS Code exten
• Unexpected function parameter ${param.type}
• updatePendingStatements: Variable for dependency "${dep}" no

AI-assisted analysis of facebook/flow@d1341dac89 (2026-08-17). Data as JSON: /api/errors/e3cc8571935c06a7. Report an issue: GitHub.