Create Extension Method in typescript - String.IsNullOrEmpty()
How to Create Extension Method using Typescript in Angular Application - String.IsNullOrEmpty()
Step 1 : Create typings.d.ts (declaration file) in the application and declare the method in interface like below.
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interface StringConstructor { isNullOrEmpty(value: string): boolean; }
Step 2 : Create extension.ts file in the application and implement the method like below.
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String.isNullOrEmpty = function (value: string): boolean { return value === undefined || value.trim() === '' || value === null; };
Step 3 : Usage of the Method in the component or class file.
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import './extensions'; export class TestComponent implements OnInit { public ngOnInit(): void { let abc; console.log(String.isNullOrEmpty(abc)); } }
Step 4 : Output like below.
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