if value in array code example
Example 1: check value exist in array javascript
[1, 2, 3].includes(2); // true
[1, 2, 3].includes(4); // false
[1, 2, 3].includes(1, 2); // false (second parameter is the index position in this array at which to begin searching)
Example 2: javascript check if in array
var extensions = ["image/jpeg","image/png","image/gif"];
if(extensions.indexOf("myfiletype") === -1){
alert("Image must be .png, .jpg or .gif");
}
Example 3: check items in array javascript
function checkAllEven(arr) {
return arr.every(function(x){
return x % 2 === 0
})
}
//using "every" to check every item in array.