js check element in array code example
Example 1: javascript array contains
var colors = ["red", "blue", "green"];
var hasRed = colors.includes("red");
var hasYellow = colors.includes("yellow");
Example 2: javascript test if it is an array
if (Array.isArray(object)) {
} else {
}
Array.isArray([1, 2, 3, 4]);
Array.isArray(4);
Example 3: js test if array
if(Array.isArray(myVarToTest)) {
} else {
}
Example 4: 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 5: see if array contains array javascript
const found = arr1.some(r=> arr2.indexOf(r) >= 0)
Example 6: check items in array javascript
function checkAllEven(arr) {
return arr.every(function(x){
return x % 2 === 0
})
}