import React, { Component } from 'react'; import pure from 'pure-render-decorator'; @pure export default class FileInput extends Component { componentWillMount() { this.input = window.document.createElement('input'); this.input.setAttribute('type', 'file'); this.input.addEventListener('change', e => { const file = e.target.files[0]; const reader = new FileReader(); reader.onload = () => { console.log(reader.result.byteLength); this.props.onChange(file.name, reader.result); }; reader.readAsArrayBuffer(file); }); } handleClick = () => this.input.click(); render() { return ( ); } }