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Today, the editor will share with you es6 and then judge whether the array has a certain value of the relevant knowledge points, 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 can get something after reading this article, let's take a look at it.

Judgment method: 1, use the "arr.includes (element value)" statement, if the return value is true, then there is an item in the array; 2, use the "arr.findIndex ((v) = > {return value = element value;})" statement, if the return value is not "- 1", then the array contains an item.

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

Es6 determines whether the array has a certain value.

Method 1: using includes () method

The includes () method is used to determine whether an array contains a specified value and returns true or false. Syntax:

Array.includes (searchElement, fromIndex)

SearchElement: the element to find

FromIndex: the index location to start the search, which can be omitted. The default value is 0.

Example:

Var arr= [2, 9, 7, 8, 9]; if (arr.indexOf (9)) {console.log ("specified value in array");} else {console.log ("no specified value in array");}

Method 2: using findIndex () method

The findIndex () method returns the index of the first element in the array that satisfies the provided test function. Otherwise,-1 is returned.

Var arr= [2, 9, 7, 8, 9]; var ret = arr.findIndex ((v) = > {return v = = 1;}); if (retorted return 1) {console.log ("specified value in the array");} else {console.log ("no specified value in the array");}

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