@cerebral/http documentation is confusing

[user1736]

Hello!
I'm new to cerebral and documentation for @cerebral/http makes me so dejected.

According to doc, I can use it like this:

import {set} from 'cerebral/operators'
import {httpGet} from '@cerebral/http/operators'
import {state, props} from 'cerebral/tags'

export default [
  httpGet(`/items/${props`itemKey`}`),
  set(state`app.currentItem`, props`result`)
]

But if I do so, I'll get the following error:

Uncaught TypeError: Cannot read property 'get' of undefined
    at Object.httpGet [as function] (httpGet.js:17)

Which says nothing to me.

So there're two problems:

1. Unclear error message If use http operators without adding HttpProvider
2. Gap in documentation, since there's no even word about I should instantiate it first in controller section.

[Guria]

Thanks for reporting. It is a very important issues on my mind. We must check docs of all modules to avoid such confusion and put prerequisites at first place.
Informative error messages when operators used without required providers is also must have for every package.
Cc @christianalfoni @edgesoft @henri @reflog

[user1736]

Some update here:

In my issue, I've used this code with dynamic url

import {set} from 'cerebral/operators'
import {httpGet} from '@cerebral/http/operators'
import {state, props} from 'cerebral/tags'

export default [
  httpGet(`/items/${props`itemKey`}`),
  set(state`app.currentItem`, props`result`)
]

which isn't working without adding a string tag at the url template beginning, like so:

import {set} from 'cerebral/operators'
import {httpGet} from '@cerebral/http/operators'
import {state, props, string} from 'cerebral/tags'

export default [
 httpGet(string`/items/${props`itemKey`}`), //see string tag before the url template? it's so easy so miss it
 set(state`app.currentItem`, props`result`)
]

I'd suggest to highlight this feature in documentation, and add more examples with dynamic urls.

[fvgoto]

Also worth rewording in docu:

// Any options defined in "Custom request"

What does Custom request mean? It's not "defined" anywhere... (I know it means options like for HttpProvider instantiation in the controller...).

[edgesoft]

@fvgoto Do you want to make a PR for this?

[christianalfoni]

Check this issue for hints on what to improve on the http documentation

[henri-hulski]

The http documentation needs also an example of using resolveObject.
resolveObject should also be documented in other places like Cerebral tags, firebase docs and http guide.

[henri-hulski]

See #1280.

[christianalfoni]

Housekeeping!