# Vue Messenger
A series of useful enhancements to Vue components props:
- [Transform props](#transform-props)
- [Enum-type props](#enum-type-props)
- [Numeric-type props](#numeric-type-props)
- [Listen for receiving props](#listen-for-receiving-props)
- [Two-way data binding props](#two-way-data-binding-props)
## Install
### Package
```bash
# yarn
yarn add vue-messenger
# or, npm
npm i vue-messenger --save
```
### CDN
- [jsDelivr](//www.jsdelivr.com/package/npm/vue-messenger)
- [UNPKG](//unpkg.com/vue-messenger/dist/)
Available as global `VueMessenger`.
## Usage
### Install mixin
#### Globally
```js
// main.js
import Vue from 'vue'
import Messenger from 'vue-messenger'
Vue.mixin(Messenger)
```
#### Locally
```js
// Component.vue
import Messenger from 'vue-messenger'
export default {
mixins: [Messenger],
// ...
}
```
### Transform props
To transform a prop, add a `transform: value => transformedValue` function to its descriptor, and use `this.local${PropName}` to get transformed prop. e.g.
#### 😑 before
```html
{{ normalizedMessage }}
```
#### 😀 after
```html
{{ localMessage }}
```
### Enum-type props
To define a enum-type prop, add a `enum` array to its descriptor, and its `default` value will be `enum[0]` if the descriptor doesn't contain `default` attribute. e.g.
#### 😑 before
```js
export default {
props: {
size: {
type: String,
default: 'small',
validator: value => ['small', 'large'].indexOf(value) >= 0
}
}
}
```
#### 😀 after
```js
export default {
props: {
size: {
type: String,
enum: ['small', 'large']
}
}
}
```
### Numeric-type props
To define a numeric-type prop, add `numeric: true` to its descriptor. Besides, you can set `infinite` to `ture` to allow infinite numbers, which are `-Infinity` and `Infinity`. e.g.
#### 😑 before
```js
export default {
props: {
count: {
type: [Number, String],
default: 0,
validator: value => !isNaN(value - parseFloat(value))
}
},
max: {
type: [Number, String],
default: Infinity,
validator: value => value === Infinity || !isNaN(value - parseFloat(value))
}
}
}
```
#### 😀 after
```js
export default {
props: {
count: {
numeric: true,
default: 0
},
max: {
numeric: true,
infinite: true,
default: Infinity
}
}
}
```
### Listen for receiving props
To listen for receiving a prop, add `on: { receive: (newValue, oldValue) => void }` object to its descriptor. e.g.
#### 😑 before
```js
export default {
props: {
count: [Number, String]
},
watch: {
count: {
immediate: true,
handler(newCount, oldCount) {
console.log(newCount, oldCount)
}
}
}
}
```
#### 😀 after
```js
export default {
props: {
count: {
type: [Number, String],
on: {
receive(newCount, oldCount) {
console.log(newCount, oldCount)
}
}
}
}
}
```
### Two-way data binding props
To apply two-way data bindings on a prop, add `sync: true` to its descriptor. Then, you can use `this.local${PropName} = newValue` or `this.send${PropName}(newValue)` to send new value to Parent component.
> If the prop is model prop, it's no need to add `sync: true` to its descriptor.
#### 😑 before
```html
