JavaScript数组去重的七种方法及特殊数据类型处理详解

function removeDuplicatesWithSet(arr) {
  return [...new Set(arr)];
}

function removeDuplicatesWithFilter(arr) {
  return arr.filter((item, index) => arr.indexOf(item) === index);
}

function removeDuplicatesWithFor(arr) {
  const uniqueArray = [];
  for (let i = 0; i < arr.length; i++) {
    if (uniqueArray.indexOf(arr[i]) === -1) {
      uniqueArray.push(arr[i]);
    }
  }
  return uniqueArray;
}

function removeDuplicatesWithDoubleFor(arr) {
  for (let i = 0; i < arr.length; i++) {
    for (let j = i + 1; j < arr.length; j++) {
      if (arr[i] === arr[j]) {
        arr.splice(j, 1);
        j--;
      }
    }
  }
  return arr;
}

function removeDuplicatesWithIndexOf(arr) {
  const uniqueArray = [];
  for (let i = 0; i < arr.length; i++) {
    if (arr.indexOf(arr[i]) === i) {
      uniqueArray.push(arr[i]);
    }
  }
  return uniqueArray;
}

function removeDuplicatesWithIncludes(arr) {
  const uniqueArray = [];
  for (let item of arr) {
    if (!uniqueArray.includes(item)) {
      uniqueArray.push(item);
    }
  }
  return uniqueArray;
}

function removeDuplicatesWithReduce(arr) {
  return arr.reduce((acc, curr) => {
    return acc.includes(curr) ? acc : [...acc, curr];
  }, []);
}

// 根据特定属性去重
const uniqueByKey = (arr, key) => {
  const seen = new Set();
  return arr.filter(item => 
    seen.has(item[key]) ? false : seen.add(item[key])
};