Here you go:
var object1 = {
role: "os_and_type",
value: "windows"
};
var object2 = {
role: "os_and_type",
value: "Android"
};
var object3 = {
role: "features",
value: "GSM"
};
function convert_objects(){
var output = [];
var temp = [];
for(var i = 0; i < arguments.length; i++){ // Loop through all passed arguments (Objects, in this case)
var obj = arguments[i]; // Save the current object to a temporary variable.
if(obj.role && obj.value){ // If the object has a role and a value property
if(temp.indexOf(obj.role) === -1){ // If the current object's role hasn't been seen before
temp.push(obj.role); // Save the index for the current role
output.push({ // push a new object to the output,
'role':obj.role,
'value':[obj.value] // but change the value from a string to a array.
});
}else{ // If the current role has been seen before
output[temp.indexOf(obj.role)].value.push(obj.value); // Save add the value to the array at the proper index
}
}
}
return output;
}
Call it like this:
convert_objects(object1, object2, object3);
You can add as many objects to the function as you'd like.