Hook and modify stdout and stderr
npm install hook-stdimport assert from 'node:assert';
import {hookStdout} from 'hook-std';
const promise = hookStdout(output => {
promise.unhook();
assert.strictEqual(output.trim(), 'unicorn');
});
console.log('unicorn');
await promise;You can also unhook using the second transform method parameter:
import assert from 'node:assert';
import {hookStdout} from 'hook-std';
const promise = hookStdout((output, unhook) => {
unhook();
assert.strictEqual(output.trim(), 'unicorn');
});
console.log('unicorn');
await promise;Hook streams in streams option, or stdout and stderr if none are specified.
Returns a Promise with a unhook() method which, when called, unhooks both stdout and stderr and resolves the Promise with an empty result.
Hook stdout.
Returns a Promise with a unhook() method which, when called, unhooks stdout and resolves the Promise with an empty result.
Hook stderr.
Returns a Promise with a unhook() method which, when called, unhooks stderr and resolves the Promise with an empty result.
Type: object
Type: boolean
Default: true
Suppress stdout/stderr output.
Type: boolean
Default: false
Automatically unhook after the first call.
Type: stream.Writable[]
Default: [process.stdout, process.stderr]
The writable streams to hook. This can be useful for libraries allowing users to configure a writable stream to write to.
Type: Function
Receives stdout/stderr as the first argument and the unhook method as the second argument. Return a string to modify it. Optionally, when in silent mode, you may return a boolean to influence the return value of .write(…).
