Basic forEach not working with Angular/Typescript

Question

I'm trying to rewrite my mobile apps using the latest Angular 6/Ionic 4. I just can't seem to get a basic forEach working. I'm trying all types of ways, but Sublime Text & Angular CLI throws errors. Please see the screenshot below. You can see the red squiggly lines in the Sublime Text Editor. The error is commented above each code block. Does anyone have any idea where I'm going wrong?

Thanks for your time - please don't hesitate to let me know if you need additional info.

array = [1, 2, 3];

  // Duplicate identifier 'array'. -- Parameter declaration expected.
  array.forEach(function(element) {
    console.log(element);
  })

  // Unexpected token. A constructor, method, accessor, or property was expected.
  this.array.forEach((key : any, val: any) => {
    console.log(val);
  })

  // Cannot find name 'array'. Did you mean 'Array'?
  array.forEach((key : any, val: any) => {
    console.log(val);
  })

  // Cannot find name 'array'. Did you mean 'Array'?
  for (let number of array) {
   console.log(number);
  }

I'd look at some of the syntax here: typescriptlang.org/docs/handbook/iterators-and-generators.html number may be reserved? github.com/Microsoft/TypeScript/issues/2536 — JGFMK
– JGFMK, Commented Oct 26, 2018 at 17:58
Post your code as text. We can't copy and paste code from an image. Blind people can't read code in an image. — JB Nizet
– JB Nizet, Commented Oct 26, 2018 at 17:59
@JBNizet sorry - just wanted you to see the squigglys in the editor. Will post code next time. — NickyTheWrench
– NickyTheWrench, Commented Oct 26, 2018 at 18:04

alokstar · Accepted Answer · 2018-10-26 18:12:08Z

3

You need to be inside methods to access component variables. Try your code in some methods or in constructor. Something like: constructor() { Your code }

Its not required that you should call it in constructor only, you can call the component variables through any methods by using this.componentVaribale inside a method. Obviously you can create local variables in methods using 'let' keyword!

edited Oct 26, 2018 at 18:12

answered Oct 26, 2018 at 17:57

alokstar

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4 Comments

NickyTheWrench Over a year ago

Yup - needed to put it in the constructor, thanks so much. Will accept answer soon.

alokstar Over a year ago

just to clarify, its not required that you should call it in constructor only, you can call the component variables through any methods by using this.componentVaribale inside a method. Obviously you can create local variables in methods using 'let' keyword!

SiddAjmera Over a year ago

@alokstar, you might want to add that to the answer.

NickyTheWrench Over a year ago

@alokstar thanks for the clarification and your time.

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

Issue

You have issue with variable declaration scoping.

Fix

Change 1 : Local variable

let array = [1,2,3]

Change 2 : Accessing instance variable by `this`.

If you want to access this you must use inside the function.

function test(){
   this.array.forEach(function(){});
}

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Oct 26, 2018 at 18:01

Sunil

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1 Comment

NickyTheWrench Over a year ago

Thank you for your time!

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Basic forEach not working with Angular/Typescript

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Change 2 : Accessing instance variable by `this`.