javascript array prototype delete the same elements in the array

In JavaScript, array is a very commonly used data structure, and it is often necessary to perform a series of operations such as adding, deleting, modifying, and checking the array. In actual development, we may encounter the need to delete the same elements in an array. This article mainly introduces how to use the prototype of the array to delete the same elements in the array.

1. Array Prototype

In JavaScript, each object has a prototype. A prototype is a property of an object that points to another object that contains shared properties and methods. When we access a property of an object, if the object itself does not have that property, the JavaScript engine looks for that property in the prototype object. Simply put, a prototype is an object used to share properties and methods.

An array is also an object, so it also has a prototype. In JavaScript, the prototype of an array is Array.prototype. This prototype object contains many useful methods, such as push, pop, shift, unshift, slice, splice, etc.

We can view the array prototype through the following code:

console.log(Array.prototype);

The output result is as follows:

[constructor: ƒ, concat: ƒ, copyWithin: ƒ, fill: ƒ, find: ƒ, …]

2. Use the array prototype to delete the same elements in the array

In JavaScript, there are many ways to delete identical elements from an array. We can use filter, reduce, forEach and other methods to achieve this. However, deleting identical elements from an array can be implemented more concisely by modifying the methods in the array prototype.

The following is a function that deletes the same elements in the array. This function uses the indexOf and splice methods in the array prototype:

Array.prototype.unique = function() {
  for (var i = 0; i < this.length; i++) {
    var index = this.indexOf(this[i], i + 1);
    if (index > -1) {
      this.splice(index, 1);
      i--;
    }
  }
  return this;
}

var arr = [1, 2, 2, 3, 3, 3, 4];
arr.unique(); // [1, 2, 3, 4]

In the above code, we first add a unique method, used to delete identical elements in an array. Then in the function, we use a for loop to traverse the array, and for each element, we use the indexOf method to find whether there are the same elements in the following elements. If the same element is found, use the splice method to remove the element from the array and decrement the counter i by 1 to prevent subsequent elements from being skipped.

Finally, we return the array after removing duplicate elements. As you can see, this method is very simple, easy to understand, and can effectively delete the same elements in the array.

3. Summary

This article mainly introduces how to use the prototype of JavaScript array to delete the same elements in the array. By modifying the prototype method, we can implement this function more concisely, thus improving development efficiency. Of course, in actual development, we should also choose the most appropriate method to operate arrays according to the specific situation to improve code execution efficiency and performance.

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