read 4.1.0: read

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify pkg:npm/read@4.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/read@4.1.0

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:05634fee6d897ffb7ffe374ebe04dc41e786fb9eaa7bad181587433ae1a02fd0","contract":["read({ prompt, default, input, output }) writes 'Prompt: (default) ' to output and resolves to the trimmed line read from input","read({ prompt, default, input, output }) resolves to String(default) when an empty line is submitted","read({ prompt, default, silent: true, input, output }) masks the default in the prompt as '(\u003cdefault hidden\u003e) '","read({ default }) rejects with 'default value must be string or number' when default is neither string nor number"],"goal":"verify pkg:npm/read@4.1.0","kind":"HOW","packages":["pkg:npm/read@4.1.0"],"schemaVersion":1,"symbols":["read"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"esm","os":"linux","osVersionBucket":"24","packageManager":"npm","runtime":"node","runtimeVersion":"22.22","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/read@4.1.0"],"schemaVersion":1,"subject":"pkg:npm/read@4.1.0","symbols":["read"],"verifierAdapter":"node-typescript@1"}

{
  "name": "verify-read",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "verify-read",
      "version": "1.0.0",
      "dependencies": {
        "read": "4.1.0"
      }
    },
    "node_modules/mute-stream": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/mute-stream/-/mute-stream-2.0.0.tgz",
      "integrity": "sha512-WWdIxpyjEn+FhQJQQv9aQAYlHoNVdzIzUySNV1gHUPDSdZJ3yZn7pAAbQcV7B56Mvu881q9FZV+0Vx2xC44VWA==",
      "license": "ISC",
      "engines": {
        "node": "^18.17.0 || >=20.5.0"
      }
    },
    "node_modules/read": {
      "version": "4.1.0",
      "resolved": "https://registry.npmjs.org/read/-/read-4.1.0.tgz",
      "integrity": "sha512-uRfX6K+f+R8OOrYScaM3ixPY4erg69f8DN6pgTvMcA9iRc8iDhwrA4m3Yu8YYKsXJgVvum+m8PkRboZwwuLzYA==",
      "license": "ISC",
      "dependencies": {
        "mute-stream": "^2.0.0"
      },
      "engines": {
        "node": "^18.17.0 || >=20.5.0"
      }
    }
  }
}

{
  "name": "verify-read",
  "version": "1.0.0",
  "private": true,
  "type": "module",
  "scripts": {
    "test": "node test/contract.mjs"
  },
  "dependencies": {
    "read": "4.1.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:npm/read@4.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/read@4.1.0"
  ]
}

import { PassThrough } from 'node:stream';
import { read } from 'read';

export async function promptFromStream(line, options = {}) {
  const input = new PassThrough();
  const output = new PassThrough();
  const chunks = [];
  output.on('data', (chunk) => {
    chunks.push(Buffer.from(chunk));
  });

  const promise = read({
    ...options,
    input,
    output,
  });

  setImmediate(() => {
    input.write(`${line}\n`);
  });

  const value = await promise;
  const renderedPrompt = Buffer.concat(chunks).toString('utf8');
  return { value, renderedPrompt };
}

import assert from 'node:assert/strict';
import { read } from 'read';
import { promptFromStream } from '../src/index.mjs';

const direct = await promptFromStream('custom-value', {
  prompt: 'Input:',
  default: 'fallback',
});
assert.equal(direct.value, 'custom-value');
assert.equal(direct.renderedPrompt, 'Input: (fallback) ');

const fallback = await promptFromStream('', {
  prompt: 'Input:',
  default: 'fallback',
});
assert.equal(fallback.value, 'fallback');
assert.equal(fallback.renderedPrompt, 'Input: (fallback) ');

const silentDefault = await promptFromStream('', {
  prompt: 'Token:',
  default: 1234,
  silent: true,
});
assert.equal(silentDefault.value, '1234');
assert.equal(silentDefault.renderedPrompt, 'Token: (<default hidden>) ');

await assert.rejects(
  () => read({ default: /** @type {any} */ ({ invalid: true }) }),
  /default value must be string or number/
);