Example
// kml is a string of KML data, geojsonObject is a JavaScript object of
// GeoJSON data
var kml = tokml(geojsonObject);
// grab name and description properties from each object and write them in
// KML
var kmlNameDescription = tokml(geojsonObject, {
    name: 'name',
    description: 'description'
});
// name and describe the KML document as a whole
var kmlDocumentName = tokml(geojsonObject, {
    documentName: 'My List Of Markers',
    documentDescription: "One of the many places you are not I am"
});
API
tokml(geojsonObject, [options])
Given GeoJSON data as an object, return KML data as a
string of XML.
options is an optional object that takes the following options:
The property to name/description mapping: while GeoJSON supports freeform
properties on each feature, KML has an expectation of name and description
properties that are often styled and displayed automatically. These options let
you define a mapping from the GeoJSON style to KML's.
- name: the name of the property in each GeoJSON Feature that contains
the feature's name
- description: the name of the property in each GeoJSON Feature that contains
the feature's description
Timestamp: KML can associate features with a moment in time via the TimeStamp tag.  GeoJSON doesn't
have a comparable field, but a custom property can be mapped
- timestamp: the name of the property in each GeoJSON Feature that contains 
a timestamp in XML Schema Time (yyyy-mm-ddThh:mm:sszzzzzz)
Document name and description: KML supports name and description properties
for the full document.
- documentName: the name of the full document
- documentDescription: the description of the full document
simplestyle-spec support:
- simplestyle: set to- trueto convert simplestyle-spec styles into KML styles
Source: https://github.com/mapbox/tokml#example