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Today, I would like to share with you the array of some and every is not the method of es6 related knowledge, detailed content, clear logic, I believe that most people still know too much about this knowledge, so share this article for your reference, I hope you will learn something after reading this article, let's take a look at it.

Some and every are es6 methods. Some () and every () are new methods to the es6 Array object. Some () is used to detect whether there are eligible elements in the array, and true; is returned as long as there is a match, while every () is used to detect whether all elements of the array meet the specified conditions.

The operating environment of this tutorial: windows7 system, ECMAScript version 6, Dell G3 computer.

Some () and every () are new methods to the es6 Array object.

Some () method: detects whether there are qualified elements in the array

Every () method: checks whether all array elements meet the specified conditions

Es6 some () method

The some () method is used to detect whether there are elements in the array that meet the specified criteria, returning true as long as there is a match, and false if it does not exist.

On the other hand, some () can also be used to check whether all the elements in the array do not meet the specified conditions, returning false if none of them match, and true if there are one or more matches.

The specific usage of some () is as follows:

Array.some (callbackfn [, thisArg])

Parameter description:

Array: required parameter, an array object.

Callbackfn: required parameter, a function that accepts up to three parameters. The some () method calls the callbackfn function for each element in array until callbackfn returns true, or until the end of the array is reached.

ThisArg: an optional parameter for which the this keyword can be referenced in the callbackfn function. If thisArg is omitted, undefined is used as the return false.

The song () method calls the callbackfn function on each array element in ascending indexing order until the callbackfn function returns true. If the element that causes callbackfn to return true is found, the some () method returns true immediately. If the callback does not return true for any element, the some () method returns false.

The callback function syntax is as follows:

Function callbackfn (value, index, array)

The user can declare the callback function with three parameters. The parameters of the callback function are described below.

Value: the value of the array element.

Index: a numeric index of array elements.

Array: the array object that contains this element.

The some () method does not call the callback function for missing elements in the array. Except for array objects, the some () method can be used by any object that has a length property and has a numerically indexed property name, such as an associative array, Arguments, and so on.

Example: detect whether the value of an element in an array is odd

If the some () method detects an even number, it returns true and indicates that it is not all odd; if no even number is detected, it indicates that it is all odd.

Function f (value, index, ar) {if (value% 2 = = 0) {return true;}} var a = [1m15, 4, 10, 10 and 11]; var evens = a.some (f); if (evens) {console.log ("not all odd"). ;} else {console.log ("all odd.") ;}

Es6 every () method

The every () method is used to determine whether all elements of the array meet the specified condition; it returns true only if all elements of the array meet the condition, otherwise it returns false.

The specific usage of every () is as follows:

Array.every (callbackfn [, thisArg])

Parameter description:

Array: required parameter, an array object.

Callbackfn: required parameter, a function that accepts up to three parameters. The every () method calls the callbackfn function for each element in array until callbackfn returns false, or until the end of the array is reached. (for the syntax of the callback function, please refer to the some () method above)

ThisArg: an optional parameter for which the this keyword can be referenced in the callbackfn function. If thisArg is omitted, undefined is used as the this value.

If the callbackfn function returns true for all array elements, the return value is true; otherwise the return value is false. If the array has no elements, the every () method returns true.

The every () method calls the callbackfn function on each array element once in ascending order until the callbackfn function returns false. If the element that causes callbackfn to return false is found, the every () method returns false; immediately. Otherwise, the every () method returns true. The every () method does not call the callback function for missing elements in the array.

Except for array objects, the every () method can be used by any object that has a length property with its own numerically indexed property name, such as associative array objects, Arguments, and so on.

Example: check whether the elements in the array are all even and prompt

Function f (value, index, ar) {if (value% 2 = = 0) {return true;} else {return false;}} var a = [2mai 4je 5je 6jing8]; if (a.every (f)) {console.log ("all even");} else {console.log ("not all even");}

These are all the contents of the article "Array some and every are not the methods of es6". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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