Js判断两个数组是否相等的几种常见场景

// 方式1
function isArrEqual1(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  return arr1.every((v, i) => v === arr2[i]);
  // return !arr1.some((v, i) => v !== arr2[i]);
  // return arr1.filter((v, i) => v !== arr2[i]).length === 0;
  // return arr1.findIndex((v, i) => v !== arr2[i]) === -1;
}

// 测试
const arr1 = [-2, "-1", 0, 0.1, 1, "2", "a", "", undefined, null],
  arr2 = [-2, "-1", 0, 0.1, 1, "2", "a", "", undefined, null];

isArrEqual1(arr1, arr2); // true

// 方式2
function isArrEqual2(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  for (let i = 0; i < arr1.length; i++) {
    if (arr1[i] !== arr2[i]) {
      return false;
    }
  }
  return true;
}

// 方式3
function isArrEqual3(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  return arr1.toString() === arr2.toString();
}

// 测试
isArrEqual3(arr1, arr2); // true

const arr3 = ['', 1, null, undefined, {}, { a: 1 }, NaN, [], [2, 3], new Date()],
  arr4 = ['', "1", undefined, null, {}, { a: 2 }, NaN, [], [2, "3"], new Date()];

isArrEqual3(arr3, arr4); // true

null == undefined // true
null === undefined // false

// 方式4
function isArrEqual4(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  return arr1.join() === arr2.join();
}

// 方式5 [推荐]
function isArrEqual5(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
  }
  return JSON.stringify(arr1) === JSON.stringify(arr2);
}

// 测试
isArrEqual5(arr1, arr2); // true
isArrEqual5(arr3, arr4); // false

const arr5 = [undefined, null, "", {}, { a: 1 }, NaN, [], [2, 3], new Date()],
  arr6 = [undefined, null, "", {}, { a: 1 }, NaN, [], [2, 3], new Date()];

isArrEqual5(arr5, arr6); // true