Ambiguous error message in assert.deepEqual with arrays with custom properties

[lovasoa]

var assert = require("assert");
var m = [1,2];
m.prop = true;
assert.deepEqual([1,2], m);

The assertion fails, as expected. But the error message is: AssertionError: [1,2] deepEqual [1,2].
This is not really helpful, and makes debugging harder.

[cjihrig]

What would you suggest as a better error message?

[lovasoa]

Maybe, if the assertion fails on a custom property in the array, then display the array as an object: AssertionError: [1,2] deepEqual {0:1, 1:2, m:true}.

[cjihrig]

IMO that message is more confusing. It also really complicates the code, which currently relies on a simple JSON.stringify(). I'm -1 on this.

[jfhbrook]

util.inspect is similarly easy to use and should show custom properties:

> util.inspect(xs)
'[ 1, 2, foo: \'foo\' ]'

[cjihrig]

I've already opened #8734 to switch to util.inspect() for other reasons, so maybe we can kill two birds with one stone if it lands.

[cjihrig]

Closed in bcff90e