let arr = [1, 2, 3, 4, 5, 6]
/* map */
function map(array, callback) {
if (!Array.isArray(array) || !array.length || typeof callback !== "function") {
return
} else {
let newArr = [];
for (let i = 0; i < array.length; i++) {
newArr[i] = callback(array[i], i, array)
}
return newArr
}
}
let newArr = map(arr, (item) => {
return item * 2
})
console.log(newArr);
/* filter */
function filter(arr, callback) {
if (!Array.isArray(arr) || !arr.length || typeof callback !== "function") {
return
} else {
let newArr = [];
for (let i = 0; i < arr.length; i++) {
if (callback(arr[i], i, arr)) {
newArr.push(arr[i])
}
}
return newArr
}
}
let a = filter(arr, (item) => {
return item > 3
})
console.log(a);轉載請註明出處，本文鏈接：https://www.uj5u.com/qita/296966.html
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