JS array method summary

The array method is often asked in interviews, which is summarized here

• Array.every()

    The every() method is used to check whether all elements of an array meet the specified criteria (provided by the function).
    var ages = [32.33.16.40];
    function checkAdult(age) {
        return age >= 18;
    }
    (function myFunction() {
        console.log(ages.every(checkAdult)); }) ()Copy the code

• Array.some()

    The //some() method checks if there are elements in an array that match the specified criteria (provided by a function).
    var ages = [32.33.16.40];
    function checkAdult(age) {
        return age >= 18;
    }
    function myFunction() {
        console.log(ages.some(checkAdult));
    }
Copy the code

• Array.forEach()

    The forEach() method is used to call each element of the array and pass the element to the callback function.
    var numbers = [4.9.16.25];
    function myFunction(item, index) {
        console.log(index,item); 
    }
    numbers.forEach(myFunction)
Copy the code

• Array.filter()

    // Filter all elements in an array to return a new array
    var ages = [32.33.16.40];
    function checkAdult(age) {
        return age >= 18;
    }
    (function myFunction() {
        console.log(ages.filter(checkAdult)); }) ()Copy the code