pretty succinct with existing de-structuring syntax:
```
const [variable = defaultValue] = [maybeUndefinedValue]
const fn = ({ key = defaultValue }) => { console.log(key); }
```
> On 11 Jan 2019, at 12:00, [email protected] wrote:
>
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> Today's Topics:
>
> 1. Syntax operator for "default assignment if value doesn't
> exits" (Sultan)
>
> From: Sultan <[email protected]>
> Subject: Syntax operator for "default assignment if value doesn't exits"
> Date: 11 January 2019 at 10:52:12 GMT
> To: es-discuss <[email protected]>
>
>
> An operator syntax for the the "typeof" pattern used to detect if a
> environment/object has a value:
>
> if (typeof variable === 'undefined') {...}
> if (typeof object.key === 'undefined') {...}
>
> This could manifest in destructuring as the following
>
> var fn = ({ key ||= 1 }) => {
> }
>
> And with variables as:
>
> var global ||= {}
>
> Equivalent code:
>
> (arg) => {
> if (typeof arg.key === 'undefined') {
> arg.key = 1
> }
> }
>
> if (typeof global === 'undefined') {
> var global = {}
> }
>
>
>
>
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