Commit a90b36fd authored by Amy Qualls's avatar Amy Qualls

Merge branch 'russell/edit-future-tense-vuex' into 'master'

Remove future tense from the Front End guide's Vuex section

See merge request gitlab-org/gitlab!49524
parents a49f02f0 7f4728d9
......@@ -6,14 +6,14 @@ info: To determine the technical writer assigned to the Stage/Group associated w
# Vuex
When there's a clear benefit to separating state management from components (e.g. due to state complexity) we recommend using [Vuex](https://vuex.vuejs.org) over any other Flux pattern. Otherwise, feel free to manage state within the components.
When there's a clear benefit to separating state management from components (for example, due to state complexity) we recommend using [Vuex](https://vuex.vuejs.org) over any other Flux pattern. Otherwise, feel free to manage state in the components.
Vuex should be strongly considered when:
- You expect multiple parts of the application to react to state changes
- There's a need to share data between multiple components
- There are complex interactions with Backend, e.g. multiple API calls
- The app involves interacting with backend via both traditional REST API and GraphQL (especially when moving the REST API over to GraphQL is a pending backend task)
- You expect multiple parts of the application to react to state changes.
- There's a need to share data between multiple components.
- There are complex interactions with Backend, for example, multiple API calls.
- The app involves interacting with backend via both traditional REST API and GraphQL (especially when moving the REST API over to GraphQL is a pending backend task).
The information included in this page is explained in more detail in the
official [Vuex documentation](https://vuex.vuejs.org).
......@@ -22,7 +22,7 @@ official [Vuex documentation](https://vuex.vuejs.org).
Vuex is composed of State, Getters, Mutations, Actions, and Modules.
When a user clicks on an action, we need to `dispatch` it. This action will `commit` a mutation that will change the state. The action itself will not update the state; only a mutation should update the state.
When a user clicks on an action, we need to `dispatch` it. This action `commits` a mutation that changes the state. The action itself does not update the state; only a mutation should update the state.
## File structure
......@@ -92,7 +92,7 @@ An action is a payload of information to send data from our application to our s
An action is usually composed by a `type` and a `payload` and they describe what happened. Unlike [mutations](#mutationsjs), actions can contain asynchronous operations - that's why we always need to handle asynchronous logic in actions.
In this file, we will write the actions that will call mutations for handling a list of users:
In this file, we write the actions that call mutations for handling a list of users:
```javascript
import * as types from './mutation_types';
......@@ -163,15 +163,15 @@ Instead of creating an mutation to toggle the loading state, we should:
- `PUT`: `updateSomething`
- `DELETE`: `deleteSomething`
As a result, we can dispatch the `fetchNamespace` action from the component and it will be responsible to commit `REQUEST_NAMESPACE`, `RECEIVE_NAMESPACE_SUCCESS` and `RECEIVE_NAMESPACE_ERROR` mutations.
As a result, we can dispatch the `fetchNamespace` action from the component and it is responsible to commit `REQUEST_NAMESPACE`, `RECEIVE_NAMESPACE_SUCCESS` and `RECEIVE_NAMESPACE_ERROR` mutations.
> Previously, we were dispatching actions from the `fetchNamespace` action instead of committing mutation, so please don't be confused if you find a different pattern in the older parts of the codebase. However, we encourage leveraging a new pattern whenever you write new Vuex stores
> Previously, we were dispatching actions from the `fetchNamespace` action instead of committing mutation, so please don't be confused if you find a different pattern in the older parts of the codebase. However, we encourage leveraging a new pattern whenever you write new Vuex stores.
By following this pattern we guarantee:
1. All applications follow the same pattern, making it easier for anyone to maintain the code
1. All data in the application follows the same lifecycle pattern
1. Unit tests are easier
1. All applications follow the same pattern, making it easier for anyone to maintain the code.
1. All data in the application follows the same lifecycle pattern.
1. Unit tests are easier.
#### Updating complex state
......@@ -215,7 +215,7 @@ While this approach works it has several dependencies:
- Correct selection of `item` in the component/action.
- The `item` property is already declared in the `closed` state.
- A new `confidential` property would not be reactive.
- Noting that `item` is referenced by `items`
- Noting that `item` is referenced by `items`.
A mutation written like this is harder to maintain and more error prone. We should rather write a mutation like this:
......@@ -245,7 +245,7 @@ A mutation written like this is easier to maintain. In addition, we avoid errors
### `getters.js`
Sometimes we may need to get derived state based on store state, like filtering for a specific prop.
Using a getter will also cache the result based on dependencies due to [how computed props work](https://vuejs.org/v2/guide/computed.html#Computed-Caching-vs-Methods)
Using a getter also caches the result based on dependencies due to [how computed props work](https://vuejs.org/v2/guide/computed.html#Computed-Caching-vs-Methods)
This can be done through the `getters`:
```javascript
......@@ -272,7 +272,10 @@ import { mapGetters } from 'vuex';
### `mutation_types.js`
From [vuex mutations docs](https://vuex.vuejs.org/guide/mutations.html):
> It is a commonly seen pattern to use constants for mutation types in various Flux implementations. This allows the code to take advantage of tooling like linters, and putting all constants in a single file allows your collaborators to get an at-a-glance view of what mutations are possible in the entire application.
> It is a commonly seen pattern to use constants for mutation types in various Flux implementations.
> This allows the code to take advantage of tooling like linters, and putting all constants in a
> single file allows your collaborators to get an at-a-glance view of what mutations are possible
> in the entire application.
```javascript
export const ADD_USER = 'ADD_USER';
......@@ -346,7 +349,7 @@ export default ({
#### Why not just ...spread the initial state?
The astute reader will see an opportunity to cut out a few lines of code from
The astute reader sees an opportunity to cut out a few lines of code from
the example above:
```javascript
......@@ -359,17 +362,17 @@ export default initialState => ({
});
```
We've made the conscious decision to avoid this pattern to aid in the
discoverability and searchability of our frontend codebase. The same applies
We made the conscious decision to avoid this pattern to improve the ability to
discover and search our frontend codebase. The same applies
when [providing data to a Vue app](vue.md#providing-data-from-haml-to-javascript). The reasoning for this is described in [this
discussion](https://gitlab.com/gitlab-org/frontend/rfcs/-/issues/56#note_302514865):
> Consider a `someStateKey` is being used in the store state. You _may_ not be
> able to grep for it directly if it was provided only by `el.dataset`. Instead,
> you'd have to grep for `some_state_key`, since it could have come from a rails
> you'd have to grep for `some_state_key`, because it could have come from a Rails
> template. The reverse is also true: if you're looking at a rails template, you
> might wonder what uses `some_state_key`, but you'd _have_ to grep for
> `someStateKey`
> `someStateKey`.
### Communicating with the Store
......@@ -426,12 +429,12 @@ export default {
#### Testing Vuex concerns
Refer to [vuex docs](https://vuex.vuejs.org/guide/testing.html) regarding testing Actions, Getters and Mutations.
Refer to [Vuex docs](https://vuex.vuejs.org/guide/testing.html) regarding testing Actions, Getters and Mutations.
#### Testing components that need a store
Smaller components might use `store` properties to access the data.
In order to write unit tests for those components, we need to include the store and provide the correct state:
Smaller components might use `store` properties to access the data. To write unit tests for those
components, we need to include the store and provide the correct state:
```javascript
//component_spec.js
......@@ -482,8 +485,9 @@ describe('component', () => {
### Two way data binding
When storing form data in Vuex, it is sometimes necessary to update the value stored. The store should never be mutated directly, and an action should be used instead.
In order to still use `v-model` in our code, we need to create computed properties in this form:
When storing form data in Vuex, it is sometimes necessary to update the value stored. The store
should never be mutated directly, and an action should be used instead.
To use `v-model` in our code, we need to create computed properties in this form:
```javascript
export default {
......@@ -521,7 +525,7 @@ export default {
};
```
Adding a few of these properties becomes cumbersome, and makes the code more repetitive with more tests to write. To simplify this there is a helper in `~/vuex_shared/bindings.js`
Adding a few of these properties becomes cumbersome, and makes the code more repetitive with more tests to write. To simplify this there is a helper in `~/vuex_shared/bindings.js`.
The helper can be used like so:
......@@ -568,4 +572,4 @@ export default {
}
```
`mapComputed` will then generate the appropriate computed properties that get the data from the store and dispatch the correct action when updated.
`mapComputed` then generates the appropriate computed properties that get the data from the store and dispatch the correct action when updated.
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