Update: check template literal in yoda (fixes #12863)

[yeonjuan]

Prerequisites checklist

• I have read the contributing guidelines.
• The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.

What is the purpose of this pull request? (put an "X" next to an item)

[ ] Documentation update
[x] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

What changes did you make? (Give an overview)

I added checking for template literals, which have no expressions.

Is there anything you'd like reviewers to focus on?

In the actual version(v6.8.0), a comparison between a literal and expression is warned, even if operands in the expressions are consist of literals only.

Online Demo

/*eslint yoda: ["error", "never"]*/

if (1 < 1 + 1) { // Error
}

if ("a" === "a" + "b") { // Error
}

if (1 < +1) {

}

From this point of view, I think template literal with only literal expressions should be warned, so added these test cases.

{
        code: "if (`${\"red\"}` <= `red`) {}",
        output: "if (`red` >= `${\"red\"}`) {}",
        options: ["always"],
        parserOptions: { ecmaVersion: 2015 },
        errors: [
            {
                messageId: "expected",
                data: { expectedSide: "left", operator: "<=" },
                type: "BinaryExpression"
            }
        ]
}

But I'm not sure whether it is intended behavior or not.

[nzakas]

The code looks good. Can you please update the documentation too?

[mdjermanovic]

Looks good! I left a couple of minor suggestions.

[mdjermanovic]

LGTM, thanks!

[kaicataldo]

Thanks for contributing!