javascript - Item 未在 foreach 循环中定义？

Question

我正在查看答案 here但在做时:

let users = [{name: 'john', address: '10 king street'}, ....];

users.forEach(item, index, object => {

我收到错误:

item is not defined

我需要这个，这样我就可以:

object.splice(index, 1);

Answer 1

将多个参数传递给箭头函数时，请将它们括在括号中:

users.forEach((item, index, object) => { ... }

(参见 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions#Syntax )

例如，要删除所有名为“john”的用户，请执行以下操作:

users.forEach((item, index, object) => {
  if(item.name == 'john') {
    object.splice(index, 1);
  }
});

片段:

let users = [
  {name: 'john', address: '10 king street'},
  {name: 'mary', address: '10 queen street'},
  {name: 'john', address: '10 prince street'},
  {name: 'hank', address: '10 duke street'}
];

users.forEach((item, index, object) => {
  if(item.name == 'john') {
    object.splice(index, 1);
  }
});

console.log(JSON.stringify(users));