Cannot pass multiple node flags

[adam-codaio]

With a simple mocharc.json:

{
  "max-old-space-size": 4096,
  "v8-allow-natives-syntax": true
  ...
}

I get the error
Error: illegal value for flag --max-old-space-size=4096 --allow-natives-syntax of type size_t

[craigtaub]

Can you supply mocha, node, os versions please. Also an MCVE.

Or better yet fill out a Bug report template please.

[juergba]

see also #3791

[adam-codaio]

Mocha: 6.0.2
Node: 10.15.1
OS: Mac Mojave 10.14.2

.mocharc.json:

{
  "max-old-space-size": 4096,
  "v8-allow-natives-syntax": true
}

test.js

var assert = require('assert');
it('is true', function(){
  assert.equal(2, 1 + 1);
});

Error:
Error: illegal value for flag --max-old-space-size=4096 --allow-natives-syntax of type size_t