js-assign v1.1.0

Background

If you are familiar with the ES6, you must have used such variable declaration in your program.

const { name = 'apple', price = 100 } = store;

Generally, you declare the name and price variable, and the default values are apple and 100. This will works well if the store is

const store = { name: 'orange', price: 99 };

or

const store = {name: 'orange'};

However, if the store is

const store = { name: 'apple', price: null };

What's the name and price now?

In fact, the name is apple, but the price is null not the default value 100 as we thought.

Solution

Here is a webpack loader called js-assign by meself. Using the loader, you can get the default value even the store is

const store = { name: 'apple', price: null };

First, add the follow function to your Global Utils file.

const proxy = (obj) => {
    return new Proxy(obj, {
        get(target, key, value) {
            if(target[key] === null) {
                return void 0;
            } else  {
                return target[key];
            }
        }
    })
}

You have to call this function by GUtils.proxy(obj).

Otherwise, you have to change the source code at src/proxy.js

Second, install the loader

npm i js-assign

Third, add the loader to your webpack config.

{
	test: /\.js$/,
	use: [
		'js-assign'
	]
}

Now, you can write the ObjectPattern as usual, the code will be transformed.

const store = { name: 'apple', price: null };
const { name = 'orange', price: 100 } = store;

Result:

const store = { name: 'apple', price: null };
const { name = 'orange', price: 100 } = GUtils.proxy(store);

Notice

This loader doesn't not support JSX. So, you should call it after babel-loader or any other loader can transform JSX to pure JS.