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1. Bind public methods to Page
Single binding
const oldPage = Page Page = function(app) { // 注意公共函数的名字不要重复,否则覆盖 app.util = function() {} return oldPage(app) }
Multiple binding, file binding
const util = require('./util.js'); // 需要绑定的函数由util文件exports出来 const oldPage = Page Page = function(app) { let newPage = Object.assign({}, util, app) return oldPage(newPage) }
2. Extension and modify the life cycle function
const oldPage = Page Page = function(app) { app.onLoad = function(options) { // 这里必须使用function, 不可以使用箭头函数, 否则this指向错误 console.log("扩展onLoad"); // onLoad函数在是当前page实例上下文中执行,所以当前的this为当前page实例 // 如果不使用call来硬绑定,而是直接app.onLoad(),那么onLoad里的this将为app这个对象 // 即我们正常在page.js里Page(app) 括号里面我们自己写的page对象 if(typeof app.onLoad === 'function') { app.onLoad.call(this, options); } } return oldPage(app) }
ps. If you want to know more about js’s knowledge about this in a more systematic way, you can click here
3. Use
When I write it myself, I encapsulate the customized content into a js file, and then reference this file in app.js
require('./init.js'); //引用即可 App({ onLaunch: function (options) { } })
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