javascript check if all objects in array have a property code example

Example 1: javascript array contains object

// Works in all browsers
if (array.index(object) !== -1) {
  console.log(`my object is in my array`)
}

// ES7 :
if(array.includes(oject)) {
  console.log(`my object is in my array`)
}

Example 2: check if all elements in array match a condition javascript

const isBelowThreshold = (currentValue) => currentValue < 40;

const array1 = [1, 30, 39, 29, 10, 13];

console.log(array1.every(isBelowThreshold));
// expected output: true