获取数组中出现次数最多的项目 JavaScript
比方说，我们需要编写一个函数，该函数接受一个字符串/数字文字数组，并返回出现次数最多的项目的索引。我们将遍历数组并准备一个frequencyMap，然后从该映射中我们将返回出现次数最多的索引。
这样做的代码是-
示例
const arr1 = [12, 5, 6, 76, 23, 12, 34, 5, 23, 34, 65, 34, 22, 67, 34];
const arr2 = [12, 5, 6, 76, 23, 12, 34, 5, 23, 34];
const mostAppearances = (arr) => {
const frequencyMap = {};
arr.forEach(el => {
if(frequencyMap[el]){
frequencyMap[el]++;
}else{
frequencyMap[el] = 1;
};
});
let highest, frequency = 0;
Object.keys(frequencyMap).forEach(key => {
if(frequencyMap[key] > frequency){
highest = parseInt(key, 10);
frequency = frequencyMap[key];
};
});
return arr.indexOf(highest);
};
console.log(mostAppearances(arr1));
console.log(mostAppearances(arr2));输出结果控制台中的输出将是-
6 1