The difference between in and of in for loop in js

The main difference between for...in and for...of loops in JavaScript is: Content: for...in traverses object properties or indexes, while for...of traverses array elements or iterables element. Order: for...in has an uncertain order, while for...of has a stable order. Variable types: for...in variables hold attribute names, while for...of variables hold element values. Termination: for...in terminates after traversing its own attributes, while for...of terminates after traversing all elements.

The difference between for...in and for...of loops in JavaScript

In JavaScript, for...in and for...of are both methods of looping through objects or arrays, but there are the following main differences in usage and traversal methods:

1. Traversing content

• for...in: Traverse the properties or indexes of the object
• for...of: Traverse the array or iterable object Elements

2. Traversal order

• for...in: The traversal order is uncertain and may Will be affected by the addition or deletion of object attributes
• for...of: The traversal order is stable and is always traversed in the order in which elements are inserted or created

3. Variable type

• for...in: The variable type is string, save the attribute or index name
• for...of: The variable type is the element value itself

4. Termination condition

• for ...in: Terminates when the loop has traversed all its own properties (excluding inherited properties)
• for...of: When the loop has traversed all iterables Terminates when element

Summary:

• Use for...in: When you need to traverse the properties or indexes of an object Name
• Use for...of: When you need to iterate over the elements of an array or iterable object themselves

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