&quot;Missing Type definition&quot; See : https://github.com/palantir/tslint/blob/master/src/rules/typedefRule.ts for details. Basically *some* annotation (for a function because `callSignature`) is missing. 

Probably the fix (specify the return type explicitly) : 

    networkStop = (action: string = null):void =&gt; {
        this.action[action] = false;
        this.net = false;
        this.netd = false;
    }

To avoid the build error.
in the **tslint.json**  file write code like:-

    &quot;typedef&quot;: [
      false,
      &quot;call-signature&quot;
    ],
This line of code in tslint.json does not make the return type of method required.

I&#39;m using *shouldChangeCharactersInRange* as a way of using on-the-fly type search.

However I&#39;m having a problem, *shouldChangeCharactersInRange* gets called before the text field actually updates:

In Objective C, I solved this using using below:

    -(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
    {
        NSString * searchStr = [textField.text stringByReplacingCharactersInRange:range withString:string];
    
        return YES;
    }

However, I&#39;ve tried writing this in Swift:

    func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -&gt; Bool {
        let txtAfterUpdate:NSString = self.projectSearchTxtFld.text as NSString
        txtAfterUpdate.stringByReplacingCharactersInRange(range, withString: string)

        self.callMyMethod(txtAfterUpdate)
        return true
    }
The method still gets called before I get a value?

How shouldChangeCharactersInRange works in Swift?

If I have the following declaration:

    float a = 3.0 ;

is that an error? I read in a book that `3.0` is a `double` value and that I have to specify it as `float a = 3.0f`. Is it so?


Is &#39;float a = 3.0;&#39; a correct statement?

I have a function in my code:

    networkStop = (action: string = null) =&gt; {
        this.action[action] = false;
        this.net = false;
        this.netd = false;
    }

I&#39;m getting a TsLint error saying:

    Message	4	TsLint: expected callSignature to have a typedef.

	

Can someone explain what this means?

What does it mean when TsLint says &quot;expected callSignature to have a typedef.&quot;

I have a function in my code:
<pre><code class="hljs language-ini">networkStop = (action: string = null) => {
 this.action[action] = false;
 this.net = false;
 this.netd = false;
}
</code></pre>
I'm getting a TsLint error saying:
<pre><code class="hljs language-arduino">Message	4	TsLint: expected callSignature to have a typedef.

</code></pre>
Can someone explain what this means?

I have the following interface and code. I thought I was doing the definitions correctly but I am getting an error:

    interface IenumServiceGetOrderBy { id: number; label: string; key: any }[];

and:

    getOrderBy = (entity): IenumServiceGetOrderBy =&gt; {
            var result: IenumServiceGetOrderBy;
            switch (entity) {
                case &quot;content&quot;:
                    result =
                    [
                        { id: 0, label: &#39;CId&#39;, key: &#39;contentId&#39; },
                        { id: 1, label: &#39;Modified By&#39;, key: &#39;modifiedBy&#39; },
                        { id: 2, label: &#39;Modified Date&#39;, key: &#39;modified&#39; },
                        { id: 3, label: &#39;Status&#39;, key: &#39;contentStatusId&#39; },
                        { id: 4, label: &#39;Status &gt; Type&#39;, key: [&#39;contentStatusId&#39;, &#39;contentTypeId&#39;] },
                        { id: 5, label: &#39;Title&#39;, key: &#39;title&#39; },
                        { id: 6, label: &#39;Type&#39;, key: &#39;contentTypeId&#39; },
                        { id: 7, label: &#39;Type &gt; Status&#39;, key: [&#39;contentTypeId&#39;, &#39;contentStatusId&#39;] }
                    ];
                    break;
            }
            return result;
        };


Error:

    Error	190	Cannot convert &#39;{}[]&#39; to &#39;IenumServiceGetOrderBy&#39;:
    	Type &#39;{}[]&#39; is missing property &#39;id&#39; from type &#39;IenumServiceGetOrderBy&#39;



How can I define an interface for an array of objects?

I am trying to instantiate new HTMLDivElement in TypeScript

    var elem = new HTMLDivElement();

but the browser throws 

    Uncaught TypeError: Illegal constructor.

The workaround seems to be to use 

    var elem = document.createElement(&#39;div&#39;);

but I find this suboptimal for various reasons. 

Why can&#39;t I instantiate DOM elements directly when there is a **new** keyword for in in the **lib.d.ts**?

    declare var HTMLDivElement: {
        prototype: HTMLDivElement;
        new (): HTMLDivElement;
    }

How to Instantiate new HTMLElement?

Does anyone know of a good, solid, implementation of C# like GUID (UUID) in TypeScript?

Could do it myself but figured I&#39;d spare my time if someone else done it before.

A TypeScript GUID class?

I&#39;m creating a TypeScript definition file for a 3rd party js library. One of the methods allows for an options object, and one of the properties of the options object accepts a string from the list: `&quot;collapse&quot;`, `&quot;expand&quot;`, `&quot;end-expand&quot;`, and `&quot;none&quot;`.

I have an interface for the options object:

    interface IOptions {
      indent_size?: number;
      indent_char?: string;
      brace_style?: // &quot;collapse&quot; | &quot;expand&quot; | &quot;end-expand&quot; | &quot;none&quot;
    }

Can the interface enforce this, so if you include an `IOptions` object with the `brace_style` property, it will only allow a string that is in the acceptable list?

How to require a specific string in TypeScript interface

I want to save my time and reuse common code across classes that extend PIXI classes (a 2d webGl renderer library).

**Object Interfaces:**

    module Game.Core {
        export interface IObject {}
    
        export interface IManagedObject extends IObject{
            getKeyInManager(key: string): string;
            setKeyInManager(key: string): IObject;
        }
    }

My issue is that the code inside `getKeyInManager` and `setKeyInManager` will not change and I want to reuse it, not to duplicate it, here is the implementation:

    export class ObjectThatShouldAlsoBeExtended{
        private _keyInManager: string;
    
        public getKeyInManager(key: string): string{
            return this._keyInManager;
        }
    
        public setKeyInManager(key: string): DisplayObject{
            this._keyInManager = key;
            return this;
        }
    }

What I want to do is to automatically add, through a `Manager.add()`, the key used in the manager to reference the object *inside* the object itself in its property `_keyInManager`.

So, let&#39;s take an example with a Texture. Here goes the `TextureManager`

    module Game.Managers {
        export class TextureManager extends Game.Managers.Manager {
    
            public createFromLocalImage(name: string, relativePath: string): Game.Core.Texture{
                return this.add(name, Game.Core.Texture.fromImage(&quot;/&quot; + relativePath)).get(name);
            }
        }
    }

When I do `this.add()`, I want the `Game.Managers.Manager` `add()` method to call a method which would exist on the object returned by `Game.Core.Texture.fromImage(&quot;/&quot; + relativePath)`. This object, in this case would be a `Texture`:

    module Game.Core {
        // I must extend PIXI.Texture, but I need to inject the methods in IManagedObject.
        export class Texture extends PIXI.Texture {
    
        }
    }

I know that `IManagedObject` is an interface and cannot contain implementation, but I don&#39;t know what to write to inject the class `ObjectThatShouldAlsoBeExtended` inside my `Texture` class. Knowing that the same process would be required for `Sprite`, `TilingSprite`, `Layer` and more.

I need experienced TypeScript feedback/advice here, it must be possible to do it, but not by multiple extends since only one is possible at the time, I didn&#39;t find any other solution.

Typescript: How to extend two classes?

**Please select at least one of the signature versions to use in Android Studio 2.3**

Now while generating a signed APK in Android Studio, it&#39;s showing two options (CheckBox) namely 1. `V1 (Jar Signature)` and 2. `V2 (Full APK Signature)` as **Signature Versions** in the last step of signed APK generating process.

[![**Signature Versions** options][1]][1]

So, what is the difference between **V1 (Jar Signature)** and **V2 (Full APK Signature)** in the new Android Studio update?

And which should I use (or both) for signing apk for play store release?

Also, I&#39;m getting error **Install Parse Failed No Certificates** while installing APK when I use the second option. 

  [1]: https://i.stack.imgur.com/1CPP5.png





Difference between signature versions - V1 (Jar Signature) and V2 (Full APK Signature) while generating a signed APK in Android Studio?

When trying to install a signed application (app-release.apk), a &quot;Blocked by Play Protect&quot; alert is shown and the app is not installed. However, an unsigned application  (app-debug.apk) can be installed without problems.

The error message: 

&gt;Play Protect doesn&#39;t recognise this app&#39;s developer. Apps from unknown developers can sometimes be unsafe.

Why this error happened? What&#39;s the solution?

![image of Error][1]

  [1]: https://i.stack.imgur.com/LlLiX.png

installation app blocked by play protect

From time to time, I get TSLint errors &quot;block is empty&quot;. This happens e.g. when I pass a no-op callback to a function:

    doSomething(() =&gt; {});

From what I read, JSLint apparently does the same, but I didn&#39;t verify that.

I find these usages completely valid, so I tried to find a reason why empty blocks are considered bad at all. But the only thing I&#39;m able to find (e.g. in [this answer](https://stackoverflow.com/a/17685875/219187)) are instructions to add a `return;` to avoid the error. This is **not** what I want to do in every empty callback.

Why does TSLint report above empty block as problem? Is there any reason why I shouldn&#39;t disable the check?

Why do TSLint and JSLint report empty blocks?

I&#39;m pretty new to TypeScript and I would like to know if there exists a good way to rewrite code to avoid TSLint error &quot;object access via string literals is disallowed&quot; in the following code

    interface ECType
    {
        name: string;
        type: string;
        elementType?: string;
    }

    export var fields: { [structName: string]: Array&lt;ECType&gt;; } = { };

    class ECStruct1 {
        foo: string;
        bar: number;
        baz: boolean;
        qux: number;
        quux: number;
        corge: ECStruct2[];
        grault: ECStruct2;

        constructor() {
            ...
        }
    } 

    fields[&#39;ECStruct1&#39;] = [
        { name: &#39;foo&#39;, type: &#39;string&#39; },
        { name: &#39;bar&#39;, type: &#39;int&#39; },
        { name: &#39;baz&#39;, type: &#39;bool&#39; },
        { name: &#39;qux&#39;, type: &#39;long&#39; },
        { name: &#39;quux&#39;, type: &#39;ulong&#39; },
        { name: &#39;corge&#39;, type: &#39;array&#39;, elementType: &#39;ECStruct2&#39; },
        { name: &#39;grault&#39;, type: &#39;ECStruct2&#39; }
    ];

**Update**: At the end the content above will be part of a self-generated file with more than 300 `ECStruct`s, so I would like to have the class definition (e.g. `ECStruct1`) followed by its meta-description (e.g. `fields[&#39;ECStruct1&#39;]`).


How to rewrite code to avoid TSLint &quot;object access via string literals&quot;

The IDE being used is WebStorm 11.0.3, the tslint is configured and works, but, it hangs because it tries to parse large *.d.ts library files. 

Is there a way to ignore a particular file or directory?

How to ignore a particular directory or file for tslint?

Is that possible to lint entire folder using tslint?

Using eslint it is possible to do `eslint ./src` to validate whole folder. 

When i try to do the same for tslint - i am getting an error `Error: EISDIR: illegal operation on a directory`. In their examples on the site - they show how to validate single file, which is not the case usually.

Is that possible to validate my project without extra things like `gulp-tslint`, just from the command line?

How to lint entire folder using tslint

Lint error message: 

&gt; src/app/detail/edit/edit.component.ts[111, 5]: for (... in ...)
&gt; statements must be filtered with an if statement

Code snippet (It is a working code. It is also available at [angular.io form validation section][1]):
 

    for (const field in this.formErrors) {
          // clear previous error message (if any)
          this.formErrors[field] = &#39;&#39;;
          const control = form.get(field);
    
          if (control &amp;&amp; control.dirty &amp;&amp; !control.valid) {
            const messages = this.validationMessages[field];
            for (const key in control.errors) {
              this.formErrors[field] += messages[key] + &#39; &#39;;
            }
          }
        }

Any idea how to fix this lint error?

  [1]: https://angular.io/docs/ts/latest/cookbook/form-validation.html

Content Type	Original Author	Original Content on Stackoverflow
Question	user1679941	View Question on Stackoverflow
Solution 1 - Typescript	basarat	View Answer on Stackoverflow
Solution 2 - Typescript	Shashikant Pandit	View Answer on Stackoverflow

What does it mean when TsLint says "expected callSignature to have a typedef."

Typescript Problem Overview

Typescript Solutions

Solution 1 - Typescript

Solution 2 - Typescript

Is 'float a = 3.0;' a correct statement?

How shouldChangeCharactersInRange works in Swift?

Attributions