This is a simple tool to generate JSON based on command-line flags. The source is a JavaScript literal with code that can reference command-line option values; the result is plain JSON.

Run metajson something.js to execute the JavaScript code in something.js and pretty-print the result. The command-line arguments are provided in a variable called $.

For example:

$ cat example.meta.js
{
  "building": "shed",
  "color": $.color,
  "contents": $.contents || "bikes",
}
$ metajson --color blue example.meta.js
{
  "building": "shed",
  "color": "blue",
  "contents": "bikes"
}