Thefind()method does not change the original array. Array Find Methods: MethodFinds indexOf()The index of the first element with a specified value lastIndexOf()The index of the last element with a specified valu
JavaScript find() 方法 JavaScript Array 对象 实例 获取数组中年龄大于 18 的第一个元素 [mycode3 type='js'] var ages = [3, 10, 18, 20]; function checkAdult(age) { return age >= 18; } function myFunction() { document.g..
The find() method returns the value of the first element in an array that pass a test (provided as a function).The find() method executes the function once for each element present in the array:If it finds an array element where the function returns a true value, find() returns the ...
The findIndex() method returns the index of the first element in an array that pass a test (provided as a function).The findIndex() method executes the function once for each element present in the array:If it finds an array element where the function returns a true value, findIndex()...
inArray方法用于检查一个元素是否存在于数组中。它接受两个参数:需要查找的元素和可选的起始索引。如果找到该元素,则返回其索引;如果未找到,则返回-1。 示例代码: 代码语言:javascript 复制 const arr = [1, 2, 3, 4, 5]; const result = $.inArray(3, arr); console.log(result); // 2 这...
ThefindIndex()method returns -1 if no match is found. ThefindIndex()method does not execute the function for empty array elements. ThefindIndex()method does not change the original array. Array Find Methods: MethodFinds indexOf()The index of the first element with a specified value ...
arguments[1] : void 0; for (var i = 0; i < len; i++) { if (i in t) { var val = t[i]; // NOTE: Technically this should Object.defineProperty at // the next index, as push can be affected by // properties on Object.prototype and Array.prototype. // But that method's...
var newArray = arr.filter(callback(element[, index[, array]])[, thisArg]) 1. 注意filter为数组中的每个元素调用一次callback函数,并利用所有使得callback返回 true 或等价于 true 的值的元素创建一个新数组。 callback只会在已经赋值的索引上被调用,对于那些已经被删除或者从未被赋值的索引不会被调用。
arr.some(callback(element[, index[, array]])[, thisArg]) 返回值: 数组中有至少一个元素通过回调函数的测试就会返回true;所有元素都没有通过回调函数的测试返回值才会为false。 some() 为数组中的每一个元素执行一次 callback 函数,直到找到一个使得 callback 返回一个“真值”(即可转换为布尔值 true 的值...
js Array.find vs Array.filter All In One js 性能优化 find 仅返回第一个匹配的数组元素; filter 返回一个新数组,包含所有匹配的数组元素; find The find() method returns the value of the first