How to determine whether it is an array in javascript

In JavaScript, you can use the isArray() method to determine whether it is an array. The syntax format is "Array.isArray(obj)"; isArray() is a static method of the Array type. You can use it to determine a value. Whether it is an array.

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

JS determines whether it is an array: use the isArray() method

JavaScript isArray() is a static method of the Array type. You can use it to determine whether a value is an array. .

var a = [1,2,3];
console.log(typeof a);  //返回“object”
console.log(Array.isArray(a));  //true

In the above code, the typeof operator can only show that the type of the array is Object, and the Array.isArray() method can directly return a Boolean value. This method is very useful in conditional expressions.

Example

In the following code, the array has a key named 2. Since the key names are all strings, the value 2 will be automatically converted into a string.

var a = [1,2,3];
console.log(2 in a);  //true
console.log('2' in a);  //true
console.log(4 in a);  //false

If a position in the array is empty, the in operator will return false.

[Recommended learning: javascript advanced tutorial]

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