iteropt

iteropt Generator

The iteropt generator function iterates over command-line options. Each iteration yields an option with option name and value or an argument with a string token value.

Example

import makeIteropt from "iteropt";

const args = [...process.argv.slice(2)];

let verbosity = 0;
let dir = process.cwd();

const iteropt = makeIteropt("vqC:", "verbose", "quiet", "dir:");

for (let {
  opt,      // set to option name if argument is option
  val,      // set to option value if option has value
  tok,      // set to un-parsed argument if not option
  err       // set to error message if parse error occurs
} of iteropt(...args)) {
  if (err) {
    console.error(err);
    process.exit(1);
  }

  switch (opt) {
    case "-v":  case "--verbose": verbosity++;  break;
    case "-q":  case "--quiet":   verbosity--;  break;
    case "-C":  case "--dir":     dir = val;    break;
  }
}

console.log("verbosity:", verbosity);
console.log("dir:", dir);

Compatibility

Option parsing is based on the GNU getopt command, which in turn is based on getopt() from <unistd.h>. Some features are not currently supported:

• allowing long options to start with "-" (-a, --alternate option)
• setting POSIXLY_CORRECT environment variable to set scanning mode
• setting GETOPT_COMPATIBLE environment variable for compatibility with shell built-ins
• specifying "::" to allow optional arguments