js中从前到后依次查找某元素

let arr = [1, 2, 3, 4, 5];
let target = 3;
let foundIndex = -1;

for (let i = 0; i < arr.length; i++) {
    if (arr[i] === target) {
        foundIndex = i;
        break; // 找到后退出循环
    }
}

if (foundIndex !== -1) {
    console.log(`元素 ${target} 在数组中的索引为 ${foundIndex}`);
} else {
    console.log(`元素 ${target} 不在数组中`);
}

let arr = [1, 2, 3, 4, 5];
let target = 3;

let foundIndex = arr.indexOf(target);

if (foundIndex !== -1) {
    console.log(`元素 ${target} 在数组中的索引为 ${foundIndex}`);
} else {
    console.log(`元素 ${target} 不在数组中`);
}

let arr = [{id: 1}, {id: 2}, {id: 3}, {id: 4}, {id: 5}];
let targetId = 3;

let foundElement = arr.find(element => element.id === targetId);

if (foundElement) {
    console.log(`找到元素:`, foundElement);
} else {
    console.log(`没有找到id为 ${targetId} 的元素`);
}