Consider adding a warnings for incorrect tagged template literal usage in development

[cesarandreu]

I was adding styled-components to an app and global styles weren't showing up. There weren't any errors and it wasn't immediately obvious what I was doing wrong. It turned out I was using injectGlobal wrong:

// wrong: calling injectGlobal as a function. oops.
injectGlobal(`html { color: red; }`)

// correct: using a tagged template literal
injectGlobal`html { color: red; }`

The first argument of tagged template literals includes a raw property. Adding a check in development to prints out an error when strings.raw is missing would help catch this kind of mistake. I'm not sure how frequently this happens, but considering the relative rarity of tagged template literal usage, I figure it wouldn't hurt.

if (process.env.NODE_ENV !== 'production' && !('raw' in strings)) {
  console.error('...')
}

[vdanchenkov]

I would suggest to check it slightly different way. injectGlobal and other helpers expect array in first argument. So, let's check for it.

Something like.

if (process.env.NODE_ENV !== 'production' && !(Array.isArray(strings))) {
  console.error('...')
}

To clarify:

injectGlobal`html { color: red; }`
// works the same way as 
injectGlobal([ `html { color: red; }` ])
// (If there is no interpolations!!!)

On the other hand, we could support incorrect usage?

injectGlobal(`html { color: red; }`) 
// will be equivalent to
injectGlobal([ `html { color: red; }`])
// or 
injectGlobal`html { color: red; }`

[mxstbr]

This seems reasonable. Whatever we can do to avoid people adding bugs to their apps 👍

[iamsolankiamit]

I'll take this one. Just to clarify, we want to allow incorrect usage or show error when incorrectly used?

[mxstbr]

Introducing an error now would be a breaking change, so let's just log a warning?

[beautyfree]

Is it still open?

[chengjianhua]

@maksugr Could you make a PR for your completed commits?

[maksugr]

@chengjianhua it is right here

[chengjianhua]

@maksugr 🤣 So this issue can be closed now?

[quantizor]

Yup