node --input-type=module: run -e and stdin code as an ES module

node --input-type=module -e "..." tells Node.js to run the code passed with -e/--eval, -p/--print or on standard input as an ES module, so import, top-level await and import.meta are available and require is not. --input-type=commonjs forces CommonJS instead. The option has no effect on files: node app.js still follows the file extension and package.json "type".

The four values

node --input-type=module -e 'import os from "node:os"; console.log("module:", typeof os.cpus, typeof require, typeof import.meta.url)'
node --input-type=commonjs -e 'console.log("commonjs:", typeof require, typeof module, typeof __filename)'
echo 'const n: number = 2; console.log("module-typescript:", n * 21)' | node --input-type=module-typescript
node --input-type=module -e 'require("node:path")' 2>&1 | grep Error
node --input-type=commonjs -e 'import fs from "node:fs"' 2>&1 | grep Error
node --input-type=esm -e '1' 2>&1 | sed 's/^.*node[^:]*: //'; echo "exit: ${PIPESTATUS[0]}"

module: function undefined string
commonjs: function object string
module-typescript: 42
ReferenceError: require is not defined in ES module scope, you can use import instead
SyntaxError: Cannot use import statement outside a module
--input-type must be "module","commonjs", "module-typescript" or "commonjs-typescript"
exit: 9

Forcing the wrong type gives the two classic module errors: require is not defined in ES module scope in a module, and Cannot use import statement outside a module in CommonJS. An unknown value is rejected with the list of accepted ones.

The -typescript values are not available together with --no-strip-types.

Do you still need it?

On current Node.js, input that contains module syntax is detected automatically:

node -e 'const { setTimeout: sleep } = await import("node:timers/promises"); await sleep(10); console.log("top-level await, detected as module")'
node -e 'console.log("no module syntax -> commonjs:", typeof require)'
echo 'console.log("stdin, module forced:", typeof require)' | node --input-type=module

top-level await, detected as module
no module syntax -> commonjs: function
stdin, module forced: undefined

Code that has no import, export or top-level await is valid CommonJS, so detection keeps it CommonJS. Pass --input-type=module when you need ES module semantics for such code anyway (strict mode by default, no require, this is undefined at top level), in scripts that must behave the same on older Node.js versions, and to skip the detection step, which first tries to compile the input as CommonJS.

Common uses

# one-liner with named imports
node --input-type=module -e 'import { readFile } from "node:fs/promises"; console.log((await readFile("package.json", "utf8")).length)'

# heredoc script in CI, run as ESM
node --input-type=module <<'EOF'
import { execSync } from "node:child_process";
console.log(execSync("git rev-parse --short HEAD").toString().trim());
EOF

For files, use .mjs or "type": "module" in package.json; the differences between the two systems are explained in require vs import.

FAQ