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JavaScript method to calculate object length

小云云
小云云Original
2017-12-09 14:22:491380browse

This article mainly introduces the method of calculating object length in JavaScript in detail. It has certain reference value. Interested friends can refer to it. I hope it can help everyone.

Calculate the length of the object, that is, get the number of object properties, as follows

Method 1:Traverse the object through for in, and determine whether it is the object itself through hasOwnProperty Enumerable properties

var obj = {"c1":1,"c2":2};
function countProperties(obj){
  for(var property in obj){
    if(Object.prototype.hasOwnProperty.call(obj,property){
      count++;
    })
  }
  return count;
}
var len = obj.length;
console.log(len);//结果为2

Method 2: Get the object’s enumerable properties through Object.keys() array, and get the object length through length

var obj = {"c1":1,"c2":2};
var arr = Object.keys(obj);
var len = arr.length;
console.log(len);//结果为2

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