function randomString(): string

Question

I want to use JavaScript code in an Angular application. I tried this:

export class MerchantNewComponent extends FormBaseComponent {

  constructor(private merchantService: MerchantService,
              private router: Router) {
    super();
  }

  function randomString() {
    var length = 40;
    var chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    var result = '';
    for (var i = length; i > 0; --i) result += chars[Math.floor(Math.random() * chars.length)];
    return result;
  }
}

But I get this error:

Does anybody know how I can use this JavaScript code in an Angular application?

One option is to declare the function outside of the class and use it in the class. — Paul A. Trzyna
– Paul A. Trzyna, Commented Feb 19, 2019 at 19:01

Edric · Accepted Answer · 2019-02-18 17:34:29Z

3

Use the TypeScript syntax to declare a method in a class:

export class MerchantNewComponent extends FormBaseComponent {

  getRandomStr(): string {
    // ...
  }
}

Notes

It's recommended to add the return type of the function next to the function declaration.
Consider renaming the function to be more descriptive and to denote that it returns a value. (like what I've done above randomString becomes getRandomStr - this clarifies what exactly the function does)

For more info, check out the TypeScript handbook on classes

EDIT: To specify an argument that should be passed into a method, see below:

getRandomStr(randomLength: number): string {
  // Do something w/ the randomLength variable
  console.log(randomLength);
  // ...
}

edited Feb 18, 2019 at 17:34

answered Feb 18, 2019 at 14:04

Edric

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2 Comments

Peter Penzov Over a year ago

What about the vars into the method?

Edric Over a year ago

You can specify an argument in between the brackets.

Nguyen Phong Thien · Accepted Answer · 2019-02-18 13:58:44Z

1

should be public randomString instead of function randomString

function can be used outside the class, if it is inside, then it is a method of the class, not a function anymore.

If you use it inside the component, you can call it by using this.randomString() or randomString() in the template

You can also use getter public get randomString() {...} then when you use it, you only need to call it as this.randomString

edited Feb 18, 2019 at 13:58

answered Feb 18, 2019 at 13:54

Nguyen Phong Thien

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1 Comment

Peter Penzov Over a year ago

Anything else to change?

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