SOURCE

var app = new Vue({
    el: '#app',
    data() {
        return {
            value: ''
        }
    },
    directives: {
        enterNumber: {
            bind: (el, binding) => {
                // 指令作用在 element-input 节点，对应原生 div.el-input (真实input节点的父节点)
                if (el.tagName.toLocaleUpperCase() !== 'INPUT') {
                    el = el.getElementsByTagName('input')[0]
                }
                el.value = el.value.replace(/[^0-9]+/g, '')
                el.handlerInput = () => {
                    if (el.inputLocking) return
                    const oldValue = el.value
                    const newValue = el.value.replace(/[^0-9]+/g, '')
                    if (oldValue !== newValue) {
                        el.value = newValue
                        el.dispatchEvent(new Event('input'))
                    }
                }
                el.handleCompositionStart = () => {
                    el.inputLocking = true
                }
                el.handleCompositionEnd = () => {
                    el.inputLocking = false
                    el.dispatchEvent(new Event('input'))
                }
                el.addEventListener('input', el.handlerInput)
                el.addEventListener('compositionstart', el.handleCompositionStart)
                el.addEventListener('compositionend', el.handleCompositionEnd)
            },
            unbind: (el, binding) => {
                // 指令作用在 element-input 节点，对应原生 div.el-input (真实input节点的父节点)
                if (el.tagName.toLocaleUpperCase() !== 'INPUT') {
                    el = el.getElementsByTagName('input')[0]
                }
                el.removeEventListener('input', el.handlerInput)
                el.removeEventListener('input', el.handleCompositionStart)
                el.removeEventListener('input', el.handleCompositionEnd)
            }
        }
    }
})

<div id="app">
    <div>{{value}}</div>
    <el-input v-model="value" v-enter-number placeholder="请输入"></el-input>
</div>