Filter through function
importance: 5
We have a built-in method arr.filter(f) for arrays. It filters all elements through the function f. If it returns true, then that element is returned in the resulting array.
Make a set of “ready to use” filters:
inBetween(a, b)– betweenaandbor equal to them (inclusively).inArray([...])– in the given array.
The usage must be like this:
arr.filter(inBetween(3,6))– selects only values between 3 and 6.arr.filter(inArray([1,2,3]))– selects only elements matching with one of the members of[1,2,3].
For instance:
/* .. your code for inBetween and inArray */
let arr = [1, 2, 3, 4, 5, 6, 7];
alert( arr.filter(inBetween(3, 6)) ); // 3,4,5,6
alert( arr.filter(inArray([1, 2, 10])) ); // 1,2Filter inBetween
function inBetween(a, b) {
return function(x) {
return x >= a && x <= b;
};
}
let arr = [1, 2, 3, 4, 5, 6, 7];
alert( arr.filter(inBetween(3, 6)) ); // 3,4,5,6Filter inArray
function inArray(arr) {
return function(x) {
return arr.includes(x);
};
}
let arr = [1, 2, 3, 4, 5, 6, 7];
alert( arr.filter(inArray([1, 2, 10])) ); // 1,2