deps/v8/src/js/i18n.js
function addWECPropertyIfDefined(object, property, value) {
  if (!IS_UNDEFINED(value)) {
    defineWECProperty(object, property, value);
  }
}
function addWECPropertyIfDefined(object, property, value) {
  if (!IS_UNDEFINED(value)) {
    defineWECProperty(object, property, value);
  }
}
Adds property to an object if the value is not undefined.
Sets all descriptors to true.