map() ：映射，对数组中的每一项运行给定函数，返回每次函数调用结果组成的函数。
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head> <body>
<script>
var arr = [, , , , , ];
var newArr = arr.map(function (value, index) {
return value * value;
}) console.log(newArr);
</script> </body> </html>
map()
filter():过滤，对数组中的每一项运行给定函数，返回满足过滤条件组成的数组。
filter()
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head> <body>
<script>
var arr = [, , , , , , , , , , ];
var newArr = arr.filter(function (value, index) {
return index % === || value >= ;
});
console.log(newArr);
</script> </body> </html>
every(): 判断数组中每一项是否满足条件，只有所有项都满足条件，才会返回true。
every()
<!DOCTYPE html>
<html lang="en"> <head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head> <body>
<script>
var arr = [, , , , ]; var newArr = arr.every(function (value, index) {
return value < ;
}) console.log(newArr);
</script> </body> </html>
some():判断数组中是否存在满足条件的项，只要有一项满足条件，就会返回true。