如何在JavaScript中檢索數組中相同值的數目？

Question

var array = ['box','box','line','time','box']

例如：箱重複幾次

Answer 1

在這裏你去：

var array = ['box','box','line','time','box'], 
    map = {}, 
    key; 

array.forEach(function(item) { 
    if (map[item] === undefined) { 
     map[item] = 1; 
    } else { 
     map[item]++; 
    } 
}); 

for (key in map) { 
    console.log(" key:", key, " repeated:", map[key]); 
}