Here you go... ``` var deep;
$.extend(!deep, object1, object2); // true $.extend(!!deep, object1, object2); // false ``` What you're asking is essentially another `!`. On Thu, May 26, 2016 at 5:02 PM, Gray Zhang <[email protected]> wrote: > I don't really know how to name this feature, but I find it quite > neccessary > > In JavaScript land there are many functions with parameters of type > boolean, and invocations to these functions do not have high readability, > for example jQuery have a `clone` method with a parameter deep of type > boolean, but when read a code like: > > ``` > $.clone(sourceObject, true); > ``` > > it's hard to understand what is that `true` stands for, a more unfamiliar > API could make this more uncomfortable: > > ``` > control.dispose(true); // does it mean "to remove DOM node or anything > else?" > ``` > > In practice we can write some comment after a boolean parameter to explain > what it is: > > ``` > control.dispose(true /* removeNode */); > ``` > > but it's a lot of work. > > In this case I think we may introduce a handy syntax called "named true" > which only transforms to the keyword `true` but have a custom name: > > ``` > control.dispost(:removeNode); > ``` > > Here a leading colon hints it is a "named true" so in parsing stage > `:removeNode` simply becomes `true`, and we can have a false value with > simply `!:removeNode`, it doesn't hit performance but notably increase > readability > > Boolean parameters is not good practice but I believe it is > not eliminated nowadays and will never be eliminated, so a more friendly > syntax could save a lot of time > > --- > > Furthermore, there are also many functions accepting an `options` > parameter including some "flag properties", flag properties are simple > properties with a boolean value, a good example is the {silent: true} flag > in many event related APIs. > > Constructing an `options` object containing flag properties are not easy, > we may repeat `: true` and `: false` many times, so with previously "named > true", I think a "named true property" could help to save time: > > ``` > model.set('foo', newValue, {:silent, :disableValidation, > !:destroyOldValue}) > ``` > > Here `:silent` is simply parsed to `silent: true` and `!:destroyOldValue` > is for `destroyOldValue: false`, it can save a large amount of code > > All syntax here are just examples, not any propose to grammar > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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