Node, when I run package.json `bin` `command` , give me `syntax error near unexpected token `(' `

Question

when I run package.json bin command , give me syntax error near unexpected token(' ` .

package.json:

 "bin": {
    "grabfilenames": "./index.js"
 }

npm link:

/usr/local/bin/grabfilenames -> /usr/local/lib/node_modules/grabfilename/index.js                                                                                                                                                                               
/usr/local/lib/node_modules/grabfilename -> /Users/dulin/workspace/grabfilename  

when I run my cli:

grabfilenames -p /Users/dulin/workspace/learn-jquery

give me an error:

/usr/local/bin/grabfilenames: line 1: syntax error near unexpected token `('
/usr/local/bin/grabfilenames: line 1: `const fs = require('fs');'

How to solve it? Thanks!

Answer 1

The documentation states that:

On install, npm will symlink that file into prefix/bin for global installs, or ./node_modules/.bin/ for local installs.

This means that npm does nothing special to your file and expect it to be executable on unix. Your bin file can be a perl script, a compiled C program, a shell script, a Ruby script or even a node.js javascript app.

Therefore what causes your app to run is not npm. It is your OS. So your script must be executable (as I said, it can even be a compiled binary).

On unix, to automatically execute a script with the correct interpreter you need to have a sh-bang as the first line in the file. For node.js I generally use this line:

#! /usr/bin/env node

You can generally just use:

#! /whatever/path/to/node

but depending on the OS or even distro node.js may be installed at different locations. So /usr/bin/env is a program that loads your default environment variables which includes $PATH that will allow the shell to automatically find where node.js is installed.