Javascript 在 CoffeeScript 中将对象数组映射到键/值对
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Mapping an array of objects to key/value pairs in CoffeeScript
提问by Thilo-Alexander Ginkel
I have an array of elements that I would like to apply a mapping to to convert it into key value pairs on a single object (to mimic an associative array).
我有一个元素数组，我想对其应用映射以将其转换为单个对象上的键值对（以模拟关联数组）。
The approach in Can destructuring assignment be used to effect a projection in CoffeeScript?does not seem to work for me as it results in a simple array instead of key/value pairs.
Can destructuring assignment 中的方法可以用于影响 CoffeeScript 中的投影吗？似乎对我不起作用，因为它导致一个简单的数组而不是键/值对。
My language of choice is CoffeeScript or JavaScript.
我选择的语言是 CoffeeScript 或 JavaScript。
An example:
一个例子：
[{name: 'a', value: 'b', other: 'c'}, {name: 'd', value: 'e', other: 'f'}]
is supposed to be transformed into:
应该转换为：
{
a: 'b',
d: 'e'
}
One-liners are preferred. ;-)
优选单衬。;-)
采纳答案by Jonathan Lonowski
To fix the syntax error, you'll have to expand { @name: @value }to:
要修复语法错误，您必须扩展{ @name: @value }为：
o = {}; o[@name] = @value; o
You can then merge the objects with $.extend()and a splat (with the empty object to avoid accidentally extending jQuery):
然后，您可以使用$.extend()和 splat合并对象（使用空对象以避免意外扩展 jQuery）：
$.extend {}, $(row).children('input').map(() -> o = {}; o[@name] = @value; o)...
Though, a simpler option would be just to use a 2-liner:
不过，一个更简单的选择就是使用 2-liner：
result = {}
$(row).children('input').each(() -> result[@name] = @value)
回答by Zirak
var arr = [{name: 'a', value: 'b', other: 'c'}, {name: 'd', value: 'e', other: 'f'}];
var obj = arr.reduce(function ( total, current ) {
total[ current.name ] = current.value;
return total;
}, {});
Pure javascript. It's practically a one liner, and it looks hawt.
纯javascript。它实际上是一个单衬里，看起来很结实。
Array.prototype.reduceis ES5, but isn't difficult to shim. Here's an example shim:
Array.prototype.reduce是 ES5，但不难填充。这是一个示例垫片：
Array.prototype.reduce = function ( fun, initVal ) {
var sum = initVal || this[ 0 ],
i = 1, len = this.length;
do {
sum = fun.call( undefined, sum, this[i], i, this );
} while ( ++i < len );
return sum;
};
arr.reduceis a sophisticated version of arr.map, which is a sophisticated version of arr.forEach. You can do this for the same effect:
arr.reduce是 的复杂版本arr.map，这是 的复杂版本arr.forEach。您可以这样做以达到相同的效果：
var obj = {};
arr.forEach(function ( val ) {
obj[ val.name ] = val.value;
});
//and using jQuery.each
var obj = {};
$.each( arr, function ( index, val ) {
obj[ val.name ] = val.value;
});
//latter version in coffeescript:
obj = {}
$.each( arr, (index, val) ->
obj[ val.name ] = val.value
)
回答by Ricardo Tomasi
values = {}
values[name] = value for {name, value} in arr
or in javascript:
或在 javascript 中：
var values = {}
arr.forEach(function(o){
values[o.name] = o.value
})
Which is almost exactly what the CoffeeScript one compiles to.
这几乎就是 CoffeeScript 编译的结果。
回答by Tieme
Or using plain ES6:
或者使用普通的 ES6：
const old = [
{name: 'a', value: 'b', other: 'c'},
{name: 'd', value: 'e', other: 'f'}
]
const transformed = Object.assign(
{},
...old.map(({name, value}) => ({ [name]: value }))
);
console.log(transformed);回答by Onato
Using Array.prototype.reduce():
var arrayOfObjects = [
{name: 'a', value: 'b', other: 'c'},
{name: 'd', value: 'e', other: 'f'}
];
arrayOfObjects.reduce(function(previousValue, currentValue, currentIndex) {
previousValue[currentValue.name] = currentValue.value;
return previousValue;
}, {})
回答by ducaale
ES6 one-liner:
ES6 单线：
const data = [{name: 'a', value: 97}, {name: 'b', value: 98}]
data.reduce((obj, e) => ({...obj, [e.name]: e.value}), {})
回答by rwitzel
Have a look at http://coffeescriptcookbook.com/chapters/arrays/creating-a-dictionary-object-from-an-array
看看http://coffeescriptcookbook.com/chapters/arrays/creating-a-dictionary-object-from-an-array
myArray = [{name: 'a', value: 'b', other: 'c'}, {name: 'd', value: 'e', other: 'f'}]
dict = {}
dict[obj['name']] = obj['value'] for obj in myArray when obj['name']?
console.log(JSON.stringify(dict, 0, 2));
This produces exactly what you want.
这正是您想要的。
