如何在Javascript中向数组添加可忽略的动态值？

Question

I am adding dynamical values to my array from two tables (datatables.js) as in here:

var formArray = {
    "valueFromA0" : table1.row(0).data()[1],
    "valueFromA1" : table1.row(1).data()[1],
    "valueFromB0" : table2.row(0).data()[1],
    "valueFromB1" : table2.row(1).data()[1]
};

These tables are also dynamically created. So some of the values (or even all of them) can be empty. I want to omit 'undefined'/empty values during the creation array. For example, say valueFromA1, valueFromB0 and valueFromB1 are undefined so it means there should be only one value in the array like this:

"valueFromA0" : "5"

Answer 1

Try this:

var formArray = {
    "valueFromA0" : "7",
    "valueFromA1" : undefined,
    "valueFromB0" : "5",
    "valueFromB1" : undefined
};

function removeEmptyEntries(obj)
{
    for(var prop in obj)
    {
        if(obj.hasOwnProperty(prop) && !obj[prop])
            delete obj[prop];
    }
}


removeEmptyEntries(formArray);
console.log(formArray);

JSFIDDLE .

Answer 2

There is no way to do it with the object literal.

var formArray = {}, tmp;
if ((tmp = table1.row(0).data()[1]) !== undefined) formArray.valueFromA0 = tmp;
if ((tmp = table1.row(1).data()[1]) !== undefined) formArray.valueFromA1 = tmp;
...

Answer 3

Try utilizing Object.keys() , Array.prototype.filter() , Array.prototype.forEach() ; create new object , set properties where value not undefined at formArray object to new object

 var formArray = { "valueFromA0" : 1, "valueFromA1" : 2, "valueFromB0" : undefined, "valueFromB1" : undefined }; // new `Object` var res = {}; Object.keys(formArray).filter(function(val) { // filter `formArray` object keys where value not `undefined` return formArray[val] !== undefined }).forEach(function(val) { // set properties , values at `res` res[val] = formArray[val]; }); console.log(res)