Javascript map accessor []

A proposed extension to bracket notation accessors in Javascript.

The map accessor allows accessing properties and calling methods on nested objects with a simple syntax.

##Examples
###Property access

Map a property from each object in an array to a new array:
``js
players = [
{id: 1, mood: 'happy'},
{id: 2, mood: 'sad'},
{id: 3}
];
`
`js
players[].mood;

> ['happy', 'sad', undefined];
`


Access properties deeply nested inside arrays:
`js
arr = [{
a: [
{ b: { c: 10 } },
{ b: { c: 15 } }
]
}, {
a: [
{ b: { c: 20 } },
{ b: { c: 25 } }
]
}];
`
`js
arr[].a[].b.c;

> [[10, 15], [20, 25]]
`


Access an index within a multidimensional array:
`js
arr = [
{ a: [{ b: 10 }, { b: 15 }] },
{ a: [{ b: 20 }, { b: 25 }] },
{ a: [{ b: 30 }, { b: 35 }] }
];
`
`js
arr[].a[1].b;

> [15, 25, 35]
`


###Method calls

Call a method in each object in an array:
`js
Player = function() {
this.mood = 'sad';
};
Player.prototype.setMood = function(mood) {
this.mood = mood;
return this.mood;
};

players = [new Player(), new Player()];
`
`js
players[].setMood('happy');

players.mood

> ['happy', 'happy'];

`


Call native methods on each object in an array:
`js
arr = [{
a: [1, 2]
}, {
a: [1, 2]
}];

`
`js
arr[].a.push(3);

arr[].a

> [[1,2,3], [1,2,3]];
`


###Map accessor call

Call map on nested properties in an array:
`js
arr = [
{ a: [{ b: 10 }, { b: 15 }] },
{ a: [{ b: 20 }, { b: 25 }] }
];
`
`js
arr[].a[].b[]((n, i) => i + n * 2);

> [
{ a: [{ b: 20 }, { b: 31 }] },
{ a: [{ b: 42 }, { b: 53 }] }
]
`


Call each function in an array, with arguments:
`js
fnArr = [
(a, b) => a + b,
(a, b) => a - b
];
`
`js
fnArr[](15, 8);

> [23, 7]

`




$3

Set each property in each object in an array:
`js
arr = [{ a: 0 }, { a: 0 }];
`
`js
arr[].a = 42;

arr[].a;

> [42, 42];
`


Set each property in a multidimensional array:
`js
arr = [{
a: [0, 0]
}, {
a: [0, 0]
}];

`
`js
arr[].a[][] = 42;

arr[].a;

> [[42, 42] [42, 42]]
`

##Requirements
A browser supporting JS Proxies.
Recent versions of Chrome, Firefox and Edge.

##How to use
- Install the map accessor babel plugin
- Test without babel plugin: Use ['_mapAccessor'] instead of []`.

##Issues
- See issues or report one