import {execa} from 'execa'; const {stdout} = await execa`npm run build`; // Print command's output console.log(stdout);

import {$} from 'execa'; const {stdout: name} = await $`cat package.json`.pipe`grep name`; console.log(name); const branch = await $`git branch --show-current`; await $`dep deploy --branch=${branch}`; await Promise.all([ $`sleep 1`, $`sleep 2`, $`sleep 3`, ]); const directoryName = 'foo bar'; await $`mkdir /tmp/${directoryName}`;

await execa({preferLocal: true})`eslint`;

const {stdout, pipedFrom} = await execa`npm run build` .pipe`sort` .pipe`head -n 2`; // Output of `npm run build | sort | head -n 2` console.log(stdout); // Output of `npm run build | sort` console.log(pipedFrom[0].stdout); // Output of `npm run build` console.log(pipedFrom[0].pipedFrom[0].stdout);

const {all} = await execa({all: true})`npm run build`; // stdout + stderr, interleaved console.log(all);

const {stdout} = await execa({stdout: ['pipe', 'inherit']})`npm run build`; // stdout is also printed to the terminal console.log(stdout);

const getInputString = () => { /* ... */ }; const {stdout} = await execa({input: getInputString()})`sort`; console.log(stdout);

// Similar to: npm run build < input.txt await execa({stdin: {file: 'input.txt'}})`npm run build`;

// Similar to: npm run build > output.txt await execa({stdout: {file: 'output.txt'}})`npm run build`;

const {stdout} = await execa({lines: true})`npm run build`; // Print first 10 lines console.log(stdout.slice(0, 10).join('\n'));

for await (const line of execa`npm run build`) { if (line.includes('WARN')) { console.warn(line); } }

let count = 0; // Filter out secret lines, then prepend the line number const transform = function * (line) { if (!line.includes('secret')) { yield `[${count++}] ${line}`; } }; await execa({stdout: transform})`npm run build`;

const response = await fetch('https://example.com'); await execa({stdin: response.body})`sort`;

import {execa} from 'execa'; import {pipeline} from 'node:stream/promises'; import {createReadStream, createWriteStream} from 'node:fs'; await pipeline( createReadStream('./input.txt'), execa`node ./transform.js`.duplex(), createWriteStream('./output.txt'), );

// parent.js import {execaNode} from 'execa'; const subprocess = execaNode`child.js`; await subprocess.sendMessage('Hello from parent'); const message = await subprocess.getOneMessage(); console.log(message); // 'Hello from child'

// child.js import {getOneMessage, sendMessage} from 'execa'; const message = await getOneMessage(); // 'Hello from parent' const newMessage = message.replace('parent', 'child'); // 'Hello from child' await sendMessage(newMessage);

// main.js import {execaNode} from 'execa'; const ipcInput = [ {task: 'lint', ignore: /test\.js/}, {task: 'copy', files: new Set(['main.js', 'index.js']), }]; await execaNode({ipcInput})`build.js`;

// build.js import {getOneMessage} from 'execa'; const ipcInput = await getOneMessage();

// main.js import {execaNode} from 'execa'; const {ipcOutput} = await execaNode`build.js`; console.log(ipcOutput[0]); // {kind: 'start', timestamp: date} console.log(ipcOutput[1]); // {kind: 'stop', timestamp: date}

// build.js import {sendMessage} from 'execa'; const runBuild = () => { /* ... */ }; await sendMessage({kind: 'start', timestamp: new Date()}); await runBuild(); await sendMessage({kind: 'stop', timestamp: new Date()});

// main.js import {execaNode} from 'execa'; const controller = new AbortController(); setTimeout(() => { controller.abort(); }, 5000); await execaNode({ cancelSignal: controller.signal, gracefulCancel: true, })`build.js`;

// build.js import {getCancelSignal} from 'execa'; const cancelSignal = await getCancelSignal(); const url = 'https://example.com/build/info'; const response = await fetch(url, {signal: cancelSignal});

import {execa, ExecaError} from 'execa'; try { await execa`unknown command`; } catch (error) { if (error instanceof ExecaError) { console.log(error); } /*  ExecaError: Command failed with ENOENT: unknown command  spawn unknown ENOENT  at ...  at ... {  shortMessage: 'Command failed with ENOENT: unknown command\nspawn unknown ENOENT',  originalMessage: 'spawn unknown ENOENT',  command: 'unknown command',  escapedCommand: 'unknown command',  cwd: '/path/to/cwd',  durationMs: 28.217566,  failed: true,  timedOut: false,  isCanceled: false,  isTerminated: false,  isMaxBuffer: false,  code: 'ENOENT',  stdout: '',  stderr: '',  stdio: [undefined, '', ''],  pipedFrom: []  [cause]: Error: spawn unknown ENOENT  at ...  at ... {  errno: -2,  code: 'ENOENT',  syscall: 'spawn unknown',  path: 'unknown',  spawnargs: [ 'command' ]  }  }  */ }

await execa`npm run build`; await execa`npm run test`;

import {execa as execa_} from 'execa'; import {createLogger, transports} from 'winston'; // Log to a file using Winston const transport = new transports.File({filename: 'logs.txt'}); const logger = createLogger({transports: [transport]}); const LOG_LEVELS = { command: 'info', output: 'verbose', ipc: 'verbose', error: 'error', duration: 'info', }; const execa = execa_({ verbose(verboseLine, {message, ...verboseObject}) { const level = LOG_LEVELS[verboseObject.type]; logger[level](message, verboseObject); }, }); await execa`npm run build`; await execa`npm run test`;