Trying to do something I would think would be very simple. I would like to import an existing JavaScript library and then call it's functions. So for example I would like to import blah.js and then call blah().
import React from 'react';
import {blah} from 'blah/js/blah.js';
class MyClass extends React.Component {
constructor() {
super();
}
componentDidMount() {
window.addEventListener('resize', this.handleResize);
}
componentWillUnmount() {
window.removeEventListener('resize', this.handleResize);
}
handleResize() {
blah.blah();
}
render() {
....
}
}
export default MyClass;
Just wondering what magical combination of things I have to do to make this work. Maybe I'm just missing the point. The example gives the error "TypeError: _blah.blah is undefined".
This question is related to
reactjs
ecmascript-6
webpack
Named exports:
Let's say you create a file called utils.js, with utility functions that you want to make available for other modules (e.g. a React component). Then you would make each function a named export:
export function add(x, y) {
return x + y
}
export function mutiply(x, y) {
return x * y
}
Assuming that utils.js is located in the same directory as your React component, you can use its exports like this:
import { add, multiply } from './utils.js';
...
add(2, 3) // Can be called wherever in your component, and would return 5.
Or if you prefer, place the entire module's contents under a common namespace:
import * as utils from './utils.js';
...
utils.multiply(2,3)
Default exports:
If you on the other hand have a module that only does one thing (could be a React class, a normal function, a constant, or anything else) and want to make that thing available to others, you can use a default export. Let's say we have a file log.js, with only one function that logs out whatever argument it's called with:
export default function log(message) {
console.log(message);
}
This can now be used like this:
import log from './log.js';
...
log('test') // Would print 'test' in the console.
You don't have to call it log when you import it, you could actually call it whatever you want:
import logToConsole from './log.js';
...
logToConsole('test') // Would also print 'test' in the console.
Combined:
A module can have both a default export (max 1), and named exports (imported either one by one, or using * with an alias). React actually has this, consider:
import React, { Component, PropTypes } from 'react';
import * as utils from './utils.js';
If you do the above, you will be able to use functions in utils.js as
utils.someFunction()
Source: Stackoverflow.com