Node - check existence of command in path

Personally I have found that the command-exists module on npm works great.

Installation

npm install command-exists

Usage

• async

  var commandExists = require('command-exists');
  
  commandExists('ls', function(err, commandExists) {
  
      if(commandExists) {
          // proceed confidently knowing this command is available
      }
  
  });
  

• promise

  var commandExists = require('command-exists');
  
  // invoked without a callback, it returns a promise
  commandExists('ls')
  .then(function(command){
      // proceed
  }).catch(function(){
      // command doesn't exist
  });
  

• sync

  var commandExistsSync = require('command-exists').sync;
  // returns true/false; doesn't throw
  if (commandExistsSync('ls')) {
      // proceed
  } else {
      // ...
  }
  

You could use whereis in Linux, and where in Windows, to see if the executable can be found

var isWin = require('os').platform().indexOf('win') > -1;

var where = isWin ? 'where' : 'whereis';

var spawn = require('child_process').spawn;

var out = spawn(where + ' ls', ['/?'], {encoding: 'utf8'});

out.on('close', function (code) {
    console.log('exit code : ' + code);
});

DON'T use child_process just for that, neither packages which use child_process internally. As Matt already answered, the most straightforward way is just checking under your Path.

Here is a NPM lookpath package which scans your $PATH or $Path.

const { lookpath } = require('lookpath');

const p = await lookpath('bash');
// "/bin/bash"

This is a Node.js port of exec.LookPath from Go.

Hope it helps