JAVASCRIPT

check if a variable is array in javascript

// inside if else check
if(Array.isArray(myVarToTest)) {
	// myVatToTest is an array
} else {
	// myVarToTest is not an array
}

check if array javascript

let names=['Jhon','David','Mark'];
console.log(Array.isArray(names));
// true

let user={id:1,name:'David'};
console.log(Array.isArray(user));
// false

let age 18;
console.log(Array.isArray(age));
// false

check if element is array javascript

Array.isArray([]) //true
Array.isArray({}) //false
Array.isArray('') //false
Array.isArray(null) //false

in javascript check is is an array or not

Array.isArray(yourItem)

js check if is array

if(Array.isArray(colors)){
    //colors is an array
}

Check If Something Is An Array or Not

Array.isArray(something);

how to check value is array or not in javascript

// how to check value is array or not in javascript
const str = "foo";
const check = Array.isArray(str);
console.log(check);
// Result: false

const arr = [1,2,3,4];
const output = Array.isArray(arr);
console.log(output);
// Result: true

js check if a variable is an array

let fruit = 'apple';
let fruits = ["apple", "banana", "mango", "orange", "grapes"];

const isArray = (arr) => Array.isArray(arr);

console.log(isArray.(fruit)); //output - false
console.log(isArray.(fruits)); //output- true

javascript check if array

let variable1 = [2, 3]
let variable2 = "test";

variable1.constructor === Array; // true
variable2.constructor === Array; // false

how to check if array

// Check if something is an Array 
// just like you do with "typeof"
Array.isArray([1, 2, 3]);	// true
Array.isArray('asdf');		// false

how to check if something is array javascript

function isArray(value) {
    return Object.prototype.toString.call(value) === "[object Array]";
}

Check if value is array

Method 1: Using the isArray method
Array.isArray(variableName)'

Method 2:
variable instanceof Array

Method 3:
variable.constructor === Array

javascript - Determine whether an array contains a value

var contains = function(needle) {
    // Per spec, the way to identify NaN is that it is not equal to itself
    var findNaN = needle !== needle;
    var indexOf;

    if(!findNaN && typeof Array.prototype.indexOf === 'function') {
        indexOf = Array.prototype.indexOf;
    } else {
        indexOf = function(needle) {
            var i = -1, index = -1;

            for(i = 0; i < this.length; i++) {
                var item = this[i];

                if((findNaN && item !== item) || item === needle) {
                    index = i;
                    break;
                }
            }

            return index;
        };
    }

    return indexOf.call(this, needle) > -1;
};

check if is array javascript

if(Object.prototype.toString.call(someVar) === '[object Array]') {
    alert('Array!');
}