js map(Number) All In One

js map(Number) All In One

map() 方法创建一个新数组，其结果是该数组中的每个元素是调用一次提供的函数后的返回值。

let newArray = arr.map(callback(currentValue[, index[, array]]) {
  // return element for newArray, after executing something
}[, thisArg]);

arr.map(Constructor)

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

demo

["1", "2", "3"].map(parseInt);
// (3) [1, NaN, NaN]

["1", "2", "3"].map(Number);
// (3) [1, 2, 3]

parseInt

Number.parseInt(string,[ radix])

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/parseInt

parseInt(string [, radix])

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt

构造函数， 立即执行

new Number(value)

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/Number

Number(value)

refs

---

---

xgqfrms 2012-2020

www.cnblogs.com 发布文章使用：只允许注册用户才可以访问！

---