In node package.json, invoke script from another script with extra parameter, in this case add mocha watcher - json

Question

in node's package.json I would like to reuse a command that I already have in a 'script'.
Here is the practical example
instead of (note the extra -w on the watch script):
"scripts": {
"test" : "./node_modules/mocha/bin/mocha --compilers coffee:coffee-script/register --recursive -R list",
"watch": "./node_modules/mocha/bin/mocha --compilers coffee:coffee-script/register --recursive -R list -w",
}
I would like to have something like
"scripts": {
"test" : "./node_modules/mocha/bin/mocha --compilers coffee:coffee-script/register --recursive -R list",
"watch": "npm run script test" + "-w",
}
which doesn't work (can't do string concats in json), but you should get what I would like
I know that npm scripts support:
- & (parallel execution)
- && (sequencial execution)
so maybe there is another option?

Answer 1

This can be done in npm#2.1.17. You don't specify your OS and the version of npm that you are using, but unless you have done something to update it, you are probably running npm#1.4.28 which does not support the syntax below.
On Linux or OSX you can update npm with sudo npm install -g npm#latest. See https://github.com/npm/npm/wiki/Troubleshooting#try-the-latest-stable-version-of-npm for a guide to updating npm on all platforms.
You should be able to do this by passing an additional argument to your script:
"scripts": {
"test": "mocha --compilers coffee:coffee-script/register --recursive -R list",
"watch": "npm run test -- -w"
}
I verified this using the following, simplified package.json:
{
"scripts": { "a": "ls", "b": "npm run a -- -l" }
}
Output:
$ npm run a
> # a /Users/smikes/src/github/foo
> ls
package.json
$ npm run b
> # b /Users/smikes/src/github/foo
> npm run a -- -l
> # a /Users/smikes/src/github/foo
> ls -l
total 8
-rw-r--r-- 1 smikes staff 55 4 Jan 05:34 package.json
$