vue.js项目beforeEnter未定义

Question

beforeEnter(el) {
   let count = this.balls.length;
   while (count--) {
       let ball = this.balls[count];
       if (ball.show) {
           let rect = ball.el.getBoundingClientRect();
           let x = rect.left - 32;
           let y = -(window.innerHeight - rect.top - 22);
           el.style.display = '';
           el.style.webkitTransform = `translate3d(0,${y}px,0)`;
           el.style.transform = `translate3d(0,${y}px,0)`;
           let inner = el.getElementsByClassName('inner-hook')[0];
           inner.style.webkitTransform = `translate3d(${x}px,0,0)`;
           inner.style.transform = `translate3d(${x}px,0,0)`;
       }
   }

上面代码

Uncaught (in promise) TypeError: Cannot read property 'style' of undefined

    at VueComponent.beforeEnter (eval at <anonymous> (app.js:744), <anonymous>:99:30)

    at Transition.p$1.callHook (eval at <anonymous> (app.js:594), <anonymous>:6843:22)

    at Transition.p$1.enter (eval at <anonymous> (app.js:594), <anonymous>:6674:8)

    at applyTransition (eval at <anonymous> (app.js:594), <anonymous>:1221:21)

    at Directive.apply (eval at <anonymous> (app.js:594), <anonymous>:4804:7)

    at Directive.update (eval at <anonymous> (app.js:594), <anonymous>:4796:10)

    at VueComponent._update (eval at <anonymous> (app.js:594), <anonymous>:8501:15)

    at Watcher.run (eval at <anonymous> (app.js:594), <anonymous>:3455:17)

    at runBatcherQueue (eval at <anonymous> (app.js:594), <anonymous>:3186:13)

    at Array.flushBatcherQueue (eval at <anonymous> (app.js:594), <anonymous>:3156:5)

报错信息

Answer 1

不能直接访问元素的style属性吧