Javascript 'property inheritance'
Is there a way to specify common elements for object literals in an array?
For example:
var array = [ {key: "hi", label: "Hi", formatter:deleteCheckboxFormatter},
{key: "hello", label: "Hello", formatter:deleteCheckboxFormatter},
{key: "wut", label: "What?", formatter:deleteCheckboxFormatter}];
All three records use the same formatter. How would you refactor开发者_如何学Go this?
A pair of alternatives come to my mind:
A helper function with the default value for the common field:
function make(key, label) {
return {'key': key, 'label': label, formatter:deleteCheckboxFormatter};
}
var array = [ make("hi", "Hi"),
make("hello", "Hello"),
make("wut", "What?")];
Or a more generic function that accepts an argument for the formatter property:
function make (formatter) {
return function (key, label) {
return {'key': key, 'label': label, 'formatter':formatter};
}
}
// a function to build objects that will have a 'fooFormatter'
var foo = make('fooFormatter');
var array = [ foo ("hi", "Hi"),
foo ("hello", "Hello"),
foo ("wut", "What?")];
And the last thing that comes to my mind is simply iterate over the array assigning the common field:
var array = [ {key: "hi", label: "Hi"},
{key: "hello", label: "Hello"},
{key: "wut", label: "What?"}];
var i = array.length;
while (i--) {
array[i].formatter = 'deleteCheckboxFormatter';
}
I used here a while loop in reverse order, because the order of iteration is not important and this type of loop performs better.
var array = [ {key: "hi", label: "Hi"},
{key: "hello", label: "Hello"},
{key: "wut", label: "What?"}];
for(var item in array)
item["formatter"] = deleteCheckboxFormatter;
You could make an object out of it using a constructor:
function Obj(key, label){
this.key = key;
this.label = label;
this.formatter = "deleteCheckboxFormatter";
}
var array = [ new Obj("hi", "Hi"),
new Obj("hello", "Hello"),
new Obj("wut", "What?") ];
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