Angular ForEach in Angular4/Typescript?

In Angular 2+ (including Angular 4), the use of AngularJS constructs like angular.forEach are typically replaced with native JavaScript constructs and TypeScript features. The modern approach uses the forEach method from arrays or for…of loops, and you can handle data manipulation using the more standard ES6 syntax.

Here’s how you can refactor your selectChildren function for Angular 4 using TypeScript:

selectChildren(data, $event: Event): void {  
  const parentChecked = data.checked;  

  // Assuming hierarchicalData is an array like [{ children: [...] }, ...]  
  this.hierarchicalData.forEach((value) => {  
    value.children.forEach((child) => {  
      child.checked = parentChecked;  
    });  
  });  
} 

you can use the for…of loop to iterate over arrays in your example. This loop is particularly useful when you don’t need the index of the elements and is often considered more readable. Here’s your example refactored using for…of:

selectChildren(data, $event: Event): void {  
  const parentChecked = data.checked;  

  // Assuming hierarchicalData is an array like [{ children: [...] }, ...]   
    for (const parent of this.hierarchicalData) { 
         for (const child of parent.children) { 
           child.checked = parentChecked; 
        }
     }
}