What are the steps to utilizing the Global extension in Angular?

Question

What are the steps to utilizing the Global extension in Angular?

While working on my Angular 12 application, I developed the following string extension:

declare global {
  interface String {
    toNumber(): number | null;
  }
}

Object.defineProperty(String.prototype, "toNumber", {
  value: function(this: string) {
    return Number(this) || null;
  }
});

However, when attempting to use this extension in an Angular component:

var number = stringValue.toNumber();

An error is thrown:

Property 'toNumber' does not exist on type 'string'.

I'm seeking advice on how best to utilize extensions like this in Angular. Should I modify the way I create the extension?

angular typescript angular12

Answer 1

Answer №1

To implement this functionality, follow these steps:

Firstly, define the signature of the extension method in the global interface. This can be done by creating a separate file named global.d.ts under the src folder or adding it to the implementation file later on:

declare global {
  interface String {
    convertToNumber(): number | null;
  }
}
export {}; // necessary for module declaration

Next, add the actual implementation of the extension method in a file named string-extension.ts within the src folder. Here's what the content should look like:

Object.defineProperty(String.prototype, "convertToNumber", {
  value(this: string) {
    return Number(this) || null;
  }
});
export {}; // needed for module declaration

Finally, import the string-extension.ts file into your app.module.ts to ensure the extension is available globally:

 import 'PATH_TO_YOUR_FILE/string-extension'

Answer 2

To implement this functionality, follow these steps:

Firstly, define the signature of the extension method in the global interface. This can be done by creating a separate file named global.d.ts under the src folder or adding it to the implementation file later on:

declare global {
  interface String {
    convertToNumber(): number | null;
  }
}
export {}; // necessary for module declaration

Next, add the actual implementation of the extension method in a file named string-extension.ts within the src folder. Here's what the content should look like:

Object.defineProperty(String.prototype, "convertToNumber", {
  value(this: string) {
    return Number(this) || null;
  }
});
export {}; // needed for module declaration

Finally, import the string-extension.ts file into your app.module.ts to ensure the extension is available globally:

 import 'PATH_TO_YOUR_FILE/string-extension'

What are the steps to utilizing the Global extension in Angular?

Answer №1

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