Node - check existence of command in path

Question

I have a unique problem where I need to use Node to iterate over several Unix-style commands and see if they exist in the path of a Windows installation.

For instance, Windows doesn't support ls natively. However, supposing someone installed git and checked to include Unix commands, it would.

I need to know whether or not ls and other commands are in the system path.

Right now, I'm using child_process to run help on each command. I then check the response of running it. This is messy and dangerous. I don't want to run 30 arbitrary commands from Node:

var spawnSync = require('child_process').spawnSync;
var out = spawnSync('ls', ['/?'], {encoding: 'utf8'});

How else can I check for the existence of these commands?

Answer 1

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 {
      // ...
  }