Code Organization
January 6, 2022

In order to improve development efficiency and project maintainability, a better way of organizing code is needed, and this article only provides an idea.


Separation of structure, style and behavior, each in its own way

Take a functional page page.js as an example, we can completely put the UI structure, style description, and behavior (JS logic) of the page in one file, and a simple page may only have one or two hundred lines without much problem.

When it comes to complex UI or complex logic, stacking all three together will result in too many lines of code, poor readability, and poor maintainability with a mix of relatively independent logic.

It is recommended to continue to do some fine-grained splitting of a page.js, splitting style descriptions into page.styles.js, organizing highly coupled variables and logic into class.js using object-oriented forms, and page.js only doing UI rendering and event dispatching.

How to improve development efficiency

Under the existing development process, each code change needs to be previewed in the simulator or on the real machine, which is a time-consuming process. However, the pure JavaScript part of the Mini Program is not dependent on the runtime environment, and this part of the code can be developed by running it on a testing framework, such as Jest.

The class.js (logic-related classes) in our code and the tool functions in the /utils directory can be run in the test framework, which saves a lot of time when writing pure JavaScript parts without relying on an emulator or a real machine, and allows us to debug the code in the test framework, thus improving development efficiency.

While the test framework brings convenience, it also places higher requirements on the "testability" of our code, such as using as many "pure functions" as possible for tool functions.


A complete look at an example


import { TEXT_STYLE } from './page.styles.js'
import TextClass from './text.class.js'

 state: {
   textInstance: null
 build() {
   this.state.textInstance = new TextClass()
 buildUI() {
   hmUI.createWidget(hmUI.widget.TEXT, {
     attr: {
       text: this.state.textInstance.getText()
     styles: TEXT_STYLE


export default class TextClass {
 constructor() {
   this.text = 'Hello World'
 getText() {
   return this.text


export const TEXT_STYLE = {
 x: px(96),
 y: px(40),
 w: px(288),
 h: px(46),
 color: 0xffffff,
 text_size: px(36),
 align_h: h.ALIGN.CENTER_H,
 align_v: h.ALIGN.CENTER_V,
 text_style: hmUI.text_style.WRAP