Wxa-core NPM | npm.io

WXA-CORE

Build and use WeChat miniprogram core function with typescript.

Installation

$ npm install --save wxa-core
Getting started
To enable experimental support for decorators, you must enable the experimentalDecorators compiler option either on the command line or in your tsconfig.json, in addition, set strictPropertyInitialization to false is required.
{
  "compilerOptions": {
    "experimentalDecorators": true,
    "strictPropertyInitialization": false
  }
}

App

Use decorator app to mark a app class which extends from App.

// app.ts
import { App, app } from "wxa-core";

@app({
  ctor(obj: any){
    // override app's construct object
    // obj.xxx=xxx;
    return obj;
  }
})
export class MyApp extends App {
  onLaunch() {
    console.log('app launched.');
  }
}

Page

Use decorator page to mark a page class which extends from Page. Page has a generic parameter (default is any) indicating the data type of current page.

The ctor function is executed after the registerHook function.
// pages/index/index.ts
import { page, Page } from 'wxa-core';

@page({ ctor(obj: any){ // override page's construct object // obj.xxx=xxx; return obj; } }) export class IndexPage extends Page { onLoad() { console.log('index page loaded.'); } }

## @computed
Add computed properties based on data, it will automatically calculate the value in the following scenarios:
  * Before page initialization;
  * After calling the setData method;
> The `ctor` function is executed after the `registerHook` function.

>:warning: Accessing the internal members of the page before the page is initialized is invalid, such as 'this.route'.
```js
import { page, computed, Page } from "wxa-core";

@page
export class MyPage extends Page {
  data = { amount: 100 };
  @computed()
  currency() {
    return this.data.amount.toFixed(2);
  }
  onLoad() {
    console.log(this.route, this.data);
  }
}

output:

{amount: 100, currency: "100.00"}

Component

Use decorator component to mark a component class which extends from Component. Component has a generic parameter (default is any) indicating the data type of current component.

@component({
  ctor(obj: any){
    // override component's construct object
    // obj.xxx=xxx;
    return obj;
  },
  lifetimes:{}, //recommend to use decorator lifetime
  observers:{}, //recommend to use decorator observer
  options:{},
  pageLifetimes:{}, //recommend to use decorator pageLifetime
  properties:{},
})
export class MyComponent extends Component {}

@bind

By default, custom component's properties will be lost, using the @bind decorator to maintain property bindings.

@component()
export class MyComponent extends Component {
  @bind
  customProp:string;
  @bind
  customFunc(){}
}

@computed

Add computed properties based on data and properties, it will automatically calculate the value in the following scenarios:

Before component initialization;
After calling the setData method;
After any property receives an external update;

:warning: Accessing the internal members of the component before the component is initialized is invalid, such as 'this.setData'.
import { component, computed, Component } from "wxa-core";

@component() export class MyComponent extends Component { data = { firstName: "Lei", lastName: "Lee" }; @computed() fullName() { const { firstName, lastName } = this.data; return ${firstName} ${lastName}; } attached() { console.log(this.data); } }

output:

{firstName: "Lei", lastName: "Lee", fullName: "Lei Lee"}

## @lifetime
Declare the lifecycle functions of components that are automatically triggered at specific points in time or when encountering special frame events. For more details, please refer to [here](https://developers.weixin.qq.com/miniprogram/dev/framework/custom-component/lifetimes.html).
>:warning:Requires miniprogram's base library version 2.2.3+
```js
import { component, lifetime, Component } from "wxa-core";

@component()
export class MyComponent extends Component {
  @lifetime
  attached() {
    console.log(this.data);
  }
}

@method

We use the method decorator to mark as the component's method.

// components/hint/hint.ts
import { Component, component, method } from "wxa-core";

@component({
  properties: {
    message: String
  }
})
export class HintComponent extends Component<{ message: string }> {
  attached() {
    console.log('hint component attached.')
  }
  @method
  alert() {
    wx.showToast({ title: this.data.message })
  }
}

@observer(fields: string)

Data listeners can be used to listen for and respond to changes in any properties and data field. For more details, please refer to here.

:warning:Requires miniprogram's base library version 2.6.1+
// components/hint/hint.ts
import { Component, component, observer } from "wxa-core";

@component({ properties: { message: String } }) export class HintComponent extends Component<{ message: string }> { attached() { console.log('hint component attached.') const message = 'Hi, message has been changed!'; setTimeout(() => this.setData({ message }), 3000); } @observer('message') messageChanged(msg: string) { console.log('message changed:', msg); // others } }

output:

app launched. hint.ts:21 message changed: Hello World! hint.ts:11 hint component attached. index.ts:9 index page loaded. hint.ts:21 message changed: Hi, message has been changed!

## @pageLifetime
Declare the lifecycle function of the page where the component is located. For more details, please refer to [here](https://developers.weixin.qq.com/miniprogram/dev/framework/custom-component/lifetimes.html).
>:warning:Requires miniprogram's base library version 2.2.3+
```js
import { component, pageLifetime, Component } from "wxa-core";

@component()
export class MyComponent extends Component {
  @pageLifetime
  show() {
    console.log('The show event is triggered on the page');
  }
}

Global hooks

Page Hook

page.registerHook(fn : (obj : object) => object) : void

import { page } from "wxa-core";

page.registerHook((obj) => {
  console.log(obj);
  return obj;
})

Component Hook

component.registerHook(fn : (obj: object) => object) : void

import { component } from "wxa-core";

component.registerHook((obj) => {
  console.log(obj);
  return obj;
})

Also see

mp-event: a simple event subscription publishing system implementation;

mp-i18n: a cross-platform i18n library for muti-miniprograms (wx、alipay、baidu、tt);

mp-modal: a helper cross-platform tool for miniprograms that can more convenient to use modal components.

mp-mem: a lightweight memoize library that can be used on both normal functions and class methods;

auto-mapping: map and convert objects automatically in typescript;

Update Logs

2.1.0
- added global function registerHook for page and componet.
- remove package reflect-metadata;
2.0.0
- added custom constructor option ctor for app, page and component decorator.
- added decorator computed for component and page;
- imported reflect-metadata;
- renamed BaseApp BasePage BaseComponent to App Page Component;
- changed decorators app and page to factory form.
- added mocha test framework for current module.
- added getTabBar api's prompt.
- added Chinese's document.
1.2.1
- added decorator bind for component;
1.2.0
- removed interface(IApp, IComponent, IPage);
- added base app class BaseApp;
1.1.1
- fixed a problem where a function is defined as a property in a component
1.1.0
- remove cpage and ccomponent decorators.
1.0.2
- added tslint;
- removed source code to reduce the module size;
- added index.d.ts file;
1.0.1
- added multipleSlots option to component options;
- added observer decorator for componet's data listener;