TypeScript

apisarev

Nov 18, 2012 at 2:00 PM

I propose to make "bind" keyword for class methods. This way you can bind "this" keyword to current class instance.

class Foo {
    public bind someMethod(): void {
        // Here .this is always current Foo instance
    }
}

compiles to

var Foo = (function () {
    function Foo() {
        this.someMethod = this.someMethod.bind(this);
    }
    Foo.prototype.someMethod = function () {
    };
    return Foo;
})();

jonturner

Coordinator

Nov 20, 2012 at 4:06 PM

This discussion has been copied to a work item. Click here to go to the work item and continue the discussion.

caroen

Nov 21, 2012 at 1:34 PM

Edited Nov 21, 2012 at 1:37 PM

this is not required...

you can simply use a "delegate" or lambda expression to do what you want:

class Foo {

    private state: string;

    constructor() {

        $('#someLinkID').bind('click', (e: JQueryEventObject) => this.handleClick(e))
    }

    private handleClick(e: JQueryEventObject) {

        this.state = "Clicked!"
    }
}

apisarev

Jan 7 at 1:50 PM

caroen wrote:

this is not required...

you can simply use a "delegate" or lambda expression to do what you want:

class Foo {

    private state: string;

    constructor() {

        $('#someLinkID').bind('click', (e: JQueryEventObject) => this.handleClick(e))
    }

    private handleClick(e: JQueryEventObject) {

        this.state = "Clicked!"
    }
}

Explained my view here

rcollette

Jan 29 at 4:25 PM

It works but the syntax is rather long. Why not have a keyword like 'self' that refers to this?

I tried finding a shortcut to this. The limitation I am having is that normally in a native JS constructor I can set a member variable _this =this and then I can simply reference _this from within object methods. TypeScript forces you to use this.property to access a property of the current object but this is not the the current object. It's kind of a catch 22.

The fact that TypeScript limits or modifies the scope of vars seems to go against the "superset JavaScript" mantra.

danfma

Feb 14 at 5:33 AM

One suggestion for this feature is to follow the kotlin way to define extension methods.

In kotlin:

fun JQueryStatic.bind(eventName:String, handler: JQuery.(JQueryEventObject) -> Unit);

// using like above

$("...").bind("event", { e -> doSomethingWithJQueryElement(this); });

Something that in TS could have these definitions:

by using interfaces:

interface JQueryStatic {
  bind(eventName: string, handler: JQuery.(JQueryEventObject) => void);
   
  // or
   
  bind(eventName: string, handler: JQuery::(JQueryEventObject) => void); // remember C++

  // or
   
  bind(eventName: string, handler: JQuery#(JQueryEventObject) => void); // remember kotlin paths
}

by using extension methods (like kotlin):

function JQueryStatic.bind(eventName: string, handler: JQuery.(JQueryEventObject) => void);

// or 

function JQueryStatic :: bind(eventName: string, handler: JQuery :: (JQueryEventObject) => void);

// or 

function JQueryStatic#bind(eventName: string, handler: JQuery#(JQueryEventObject) => void);

apisarev Nov 18, 2012 at 2:00 PM	I propose to make "bind" keyword for class methods. This way you can bind "this" keyword to current class instance. class Foo { public bind someMethod(): void { // Here .this is always current Foo instance } } compiles to var Foo = (function () { function Foo() { this.someMethod = this.someMethod.bind(this); } Foo.prototype.someMethod = function () { }; return Foo; })();

jonturner Coordinator Nov 20, 2012 at 4:06 PM	This discussion has been copied to a work item. Click here to go to the work item and continue the discussion.

caroen Nov 21, 2012 at 1:34 PM Edited Nov 21, 2012 at 1:37 PM	this is not required... you can simply use a "delegate" or lambda expression to do what you want: class Foo { private state: string; constructor() { $('#someLinkID').bind('click', (e: JQueryEventObject) => this.handleClick(e)) } private handleClick(e: JQueryEventObject) { this.state = "Clicked!" } }

apisarev Jan 7 at 1:50 PM	caroen wrote: this is not required... you can simply use a "delegate" or lambda expression to do what you want: class Foo { private state: string; constructor() { $('#someLinkID').bind('click', (e: JQueryEventObject) => this.handleClick(e)) } private handleClick(e: JQueryEventObject) { this.state = "Clicked!" } } Explained my view here

rcollette Jan 29 at 4:25 PM	It works but the syntax is rather long. Why not have a keyword like 'self' that refers to this? I tried finding a shortcut to this. The limitation I am having is that normally in a native JS constructor I can set a member variable _this =this and then I can simply reference _this from within object methods. TypeScript forces you to use this.property to access a property of the current object but this is not the the current object. It's kind of a catch 22. The fact that TypeScript limits or modifies the scope of vars seems to go against the "superset JavaScript" mantra.

danfma Feb 14 at 5:33 AM	One suggestion for this feature is to follow the kotlin way to define extension methods. In kotlin: `fun JQueryStatic.bind(eventName:String, handler: JQuery.(JQueryEventObject) -> Unit); // using like above $("...").bind("event", { e -> doSomethingWithJQueryElement(this); });` Something that in TS could have these definitions: by using interfaces: `interface JQueryStatic { bind(eventName: string, handler: JQuery.(JQueryEventObject) => void); // or bind(eventName: string, handler: JQuery::(JQueryEventObject) => void); // remember C++ // or bind(eventName: string, handler: JQuery#(JQueryEventObject) => void); // remember kotlin paths }` by using extension methods (like kotlin): `function JQueryStatic.bind(eventName: string, handler: JQuery.(JQueryEventObject) => void); // or function JQueryStatic :: bind(eventName: string, handler: JQuery :: (JQueryEventObject) => void); // or function JQueryStatic#bind(eventName: string, handler: JQuery#(JQueryEventObject) => void);`

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Bind "this" keyword in method to current class instance with a keyword

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