Add a new rule no-unused-expressions

[job13er]

This project uses semver, please check the scope of this pr:

• #patch# - backwards-compatible bug fix
• #minor# - adding functionality in a backwards-compatible manner
• #major# - incompatible API change

CHANGELOG

• Added an additional rule: no-unused-expressions which will disallow expect(foo).to.be.true style assertions. See this issue for more info.

[sandersky]

👍

[job13er]

👍

[coveralls]

Changes Unknown when pulling 5b47440 on job13er:add-rule into * on ciena-frost:master*.

[juwara0]

We should turn on the ternary operators in your expressions flag: http://eslint.org/docs/rules/no-unused-expressions#options

[job13er]

We should turn on the ternary operators in your expressions flag: http://eslint.org/docs/rules/no-unused-expressions#options

Should we? I wasn't under the impression that this would prevent desirable use of ternary operators, only those where you don't actually assign the value to something. I don't know that we want to encourage the use of ternary operators over if statements if all you're doing is executing something.

Do we really want to see

(shouldItBeDone) ? doIt() : doNotDoIt()

instead of

if (shouldItBeDone) {
  doIt()
} else {
  doNotDoIt()
}

???

EDIT: I just confirmed that the rule allows normal use of ternary operators w/o a problem, it only complains if it's an unused expression.

Is the above what you'd like to be able to do, @juwara0?

[job13er]

OK, fine, someone else seems to like that too. While I personally don't like it at all I'll concede that it's not horrible, so I'll add the flag.

[coveralls]

Changes Unknown when pulling f07085a on job13er:add-rule into * on ciena-frost:master*.