详解js中Array的方法及技巧

var numbers = [65, 44, 12, 4], changedValue;
function multiplyArrayElement(num) {
 return num * 2;
}
(function myFunction() {
 changedValue = numbers.map(multiplyArrayElement);
})()
console.log(changedValue);

var ages = [32, 33, 16, 40], changedValue; 
function checkAdult(age) {
 return age >= 18;
}
(function myFunction() {
 changedValue = ages.filter(checkAdult);
})()
console.log(changedValue);

var ages = [3, 10, 18, 20], changedValue;
function checkAdult(age) {
 return age >= 18;
}
(function myFunction() {
 changedValue = ages.some(checkAdult);
})()
console.log(changedValue);

var ages = [32, 33, 16, 40], changedValue;
function checkAdult(age) {
 return age >= 18;
}
(function myFunction() {
 changedValue = ages.every(checkAdult);
})()
console.log(changedValue);

var numbers = [4, 9, 16, 25],changedValue;
function myFunction(item, index, arr) {
 arr[index] = item + 1; 
}
numbers.forEach(myFunction);
console.log(numbers);