code: function checkProperty(i) {
    const start = i;
    let l;
  
    if (l = checkProperty1(i)) tokens[start].propertyType = 1;
    else if (l = checkProperty2(i)) tokens[start].propertyType = 2;
    else if (l = checkProperty3(i)) tokens[start].propertyType = 3;
  
    return l;
  }
docs: Check if token is part of a property
  @param {Number} i Token's index number
  @return {Number} Length of the property