microsoft/TypeScript · error · Error

Expected ${inputDir} to be a directory

Error message

Expected ${inputDir} to be a directory

What it means

produceLKG.mjs copies each localization directory from `source` to `dest`. For every name in localizationDirectories it stats the source path and throws if it isn't a directory, so a partial localization build can't be copied into the LKG.

Source

Thrown at scripts/produceLKG.mjs:34

    console.log(`Building LKG from ${source} to ${dest}`);
    await fs.promises.rm(dest, { recursive: true, force: true });
    await fs.promises.mkdir(dest, { recursive: true });
    await copyLibFiles();
    await copyLocalizedDiagnostics();
    await copyTypesMap();
    await copyScriptOutputs();
    await copyDeclarationOutputs();
    await writeGitAttributes();
}

async function copyLibFiles() {
    await copyFilesWithGlob("lib?(.*).d.ts");
}

async function copyLocalizedDiagnostics() {
    for (const d of localizationDirectories) {
        const inputDir = path.join(source, d);
        if (!fs.statSync(inputDir).isDirectory()) throw new Error(`Expected ${inputDir} to be a directory`);
        const outputDir = path.join(dest, d);
        await fs.promises.mkdir(outputDir, { recursive: true });
        for (const f of await fs.promises.readdir(inputDir)) {
            const inputFile = path.join(inputDir, f);
            if (!fs.statSync(inputFile).isFile()) throw new Error(`Expected ${inputFile} to be a file`);
            const outputFile = path.join(outputDir, f);
            await fs.promises.copyFile(inputFile, outputFile);
        }
    }
}

async function copyTypesMap() {
    await copyFromBuiltLocal("typesMap.json"); // Cannot accommodate copyright header
}

async function copyScriptOutputs() {
    await copyFromBuiltLocal("tsc.js");
    await copyFromBuiltLocal("_tsc.js");

View on GitHub (pinned to b465fdbfe1)

Solutions

1. Run the full localization build before invoking produceLKG.
2. Inspect the path in the error message and ensure it exists as a directory.
3. Clean `built/` (`git clean -fdx built/`) and rebuild end-to-end.

import fs from "fs";
for (const d of localizationDirectories) {
  const p = path.join(source, d);
  const st = fs.statSync(p);
  if (!st.isDirectory()) throw new Error(`Expected ${p} to be a directory`);
}

When it happens

Trigger: A name in localizationDirectories resolves to a non-existent path or a file rather than a directory under `source`.

Common situations: Skipping the localize/L10n build step; a stray file where a directory is expected; previous build left inconsistent state.

Related errors

• Cannot replace the LKG unless all built targets are present
• Expected ${inputFile} to be a file
• LKG cannot be created when --bundle=false
• Diagnostic code ${code} appears more than once.
• tsserverlibrary requires CommonJS; use typescript.js instead

AI-assisted analysis of microsoft/TypeScript@b465fdbfe1 (2026-08-12). Data as JSON: /api/errors/5d56e9767d5e3a49. Report an issue: GitHub.