版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/qq_20087231/article/details/83343837
// 形参设置默认值
// function sum(num1, num2) {
// num1 = num1 || 10;
// num2 = num2 || 10;
// console.log(num1 + num2);
// }
// sum();
// function sum(num1 = 20, num2 = 10) {
// console.log(num1 + num2);
// }
// sum();
// sum(22);
// 参数形式 延展操作符
/*
function sum() {
let result = 0;
for (let value of arguments) {
result += value;
}
return result;
}
function sum(...nums) {
let result = 0;
for (let value of nums) {
result += value;
}
return result;
}
console.log(sum(10, 20, 30, 50));
*/
// 通过延展操作符多样化的传递参数
function sum(name, age, ...nums) {
let result = 0;
console.log(name);
console.log(age);
for (let value of nums) {
result += value;
}
return result;
}
console.log(sum('wen', 22, 10, 20, 30, 50));
// 箭头函数 () => {}
let sum = (num1, num2) => {
return num1 + num2;
};
console.log(sum(100, 300));
let nameArr = ['张三', '李四', '王五'];
nameArr.forEach((index, value) => {
console.log(index + ':' + value);
});
// 解决this指向的问题
function demo() {
setTimeout(function() {
console.log(this); // 指向Window
}, 1000);
setTimeout(() => {
console.log(this); // 指向对象本身,这里会是{}对象
}, 1000);
}
let obj = {};
demo.call(obj);