eiu165 eiu165 - 7 months ago 11
Javascript Question

How to iterate through property names of JavaScript object?

I would like to get the property names from a javascript object to build a table dynamically. Example:

var obj = {'fname': 'joe', 'lname': 'smith', 'number': '34'};

for (var i = 0; i < obj.properties.length; i++) {
alert(' name=' + obj.properties[i].name + ' value=' + obj.properties[i].value);
}


would alert:

name=fname value=joe

name=lname value=smith

name=number value=34


Then I could build a table using object like this:

var obj = { 'players': [
{ 'fname': 'joe', 'lname': 'smith', 'number': '34'} ,
{ 'fname': 'jim', 'lname': 'Hoff', 'number': '12'} ,
{ 'fname': 'jack', 'lname': 'jones', 'number': '84'}
] };


to produce:

| fname | lname | number |
|-------|--------|---------|
| joe | smith | 34 |
| jim | Hoff | 12 |
| jack | jones | 84 |


UPDATE



thanks to the answer I have produced a table from the javascipt objects using the property names from the first object in the list for the headers

function renderData() {
var obj = { 'players': [
{ 'fname': 'joe', 'lname': 'smith', 'number': '34' },
{ 'fname': 'jim', 'lname': 'jones', 'number': '12' },
{ 'fname': 'jack', 'lname': 'Hoff', 'number': '84' }
] };

var cols = GetHeaders(obj);

$('#Output').html(CreateTable(obj, cols));
}


function CreateTable(obj, cols) {
var table = $('<table></table>');
var th = $('<tr></tr>');
for (var i = 0; i < cols.length; i++) {
th.append('<th>' + cols[i] + '</th>');
}
table.append(th);

for (var j = 0; j < obj.players.length; j++) {
var player = obj.players[j];
var tr = $('<tr></tr>');
for (var k = 0; k < cols.length; k++) {
var columnName = cols[k];
tr.append('<td>' + player[columnName] + '</td>');
}
table.append(tr);
}
return table;
}



function GetHeaders(obj) {
var cols = new Array();
var p = obj.players[0];
for (var key in p) {
//alert(' name=' + key + ' value=' + p[key]);
cols.push(key);
}
return cols;
}

Answer

Use for...in loop:

for (var key in obj) {
   console.log(' name=' + key + ' value=' + obj[key]);

   // do some more stuff with obj[key]
}