标签：intercept use ott sed ... rmi sel back ons
A JavaScript Proxy allows you to intercept operations performed on objects, arrays, or functions like property lookup, assignment, invocation, property deletion, and more to add custom behavior. In this lesson we look at how to intercept property lookup with the get "trap" that will allow us to get items starting from the end of the array with ease.
console.clear() const characters = [ ‘Harry Potter‘, ‘Ron Weasly‘, ‘Hermione Granger‘, ‘Nevel Longbottom‘, ‘Lavender Brown‘, ‘Scabbers‘, ‘Pigwidgeon‘, ] const handler = { // target: the array itself // name: the index which passed in get(target, name) { // check whether index is 0,1...6 if(name in target) { // if yes, then get the value back return Reflect.get(target, name) } else { // if not, then the name is -1, -2, -3... const index = Number(name); return Reflect.get(target, target.length + index) } } } const proxy = new Proxy(characters, handler) console.log(proxy[3]); // Nevel Longbottom console.log(proxy[0]); // Harry Potter console.log(proxy[-2]); // Scabbers
标签：intercept use ott sed ... rmi sel back ons
原文地址：http://www.cnblogs.com/Answer1215/p/6275341.html
